12 day itinerary (Rome,Florence,Venice-3days each; Naples+Pompeii+Amalfi+Capri+Sorrento-3days?)

You've clarified that you are arrival and departure city is Venice someone will make a suggestion that you fly into Venice and out of Rome.
Are you going solo ? That makes a difference. If so this is a whirlwind but doable.
I agree Pisa; make that decision when you get to Florence as a daytrip.
Use just 3 hotels to cover the whole trip.
Many will say less is more but since you believe you won't have chance to return then go for it all.

Unfortunately, I already booked my plane ticket months ago. It was a deal for about $400 roundtrip out of a few US cities (I chose Dallas), but was not open-jaw.

I'm going solo to Rome and to the AC. My friend, who is currently living in Brussels, may meet me in Florence during his Easter break.

Why does it make a difference if I'm going solo?

Also, I'm 24. I'm relatively energetic and I like to be on the move constantly. Hopefully that helps.

I'm airbnb'ing most, if not all, my stays. I've only booked the 3 nights in Rome so far.
What do you think about my Naples+Pompeii+Amalfi+Capri+Sorrento in 3 days itinerary? This is the one that's making me the most nervous.

This plan would give you some flexibility, with the option to go flat out and include Pompeii, Naples, Siena and Pisa if you wish. The good thing is that no pre-commitment is required for any of them - decide on the day !!

April 6th, 11AM -- Scheduled flight arrival in Venice Marco
April 6th, 7PM -- Take ItaloReno from Venice->Rome
April 6th, 10:45PM -- Arrival in Rome for 4 nights. (Airbnb BOOKED)
April 7-9th -- Rome
April 10th -- Train via stop in Pompeii (store luggage) to Sorrento for 2 nights
April 11th -- Amalfi Coast (or Isle of Capri)
April 12th -- Train via stop in Naples (store luggage) to Florence for 3 nights
April 13th -- Florence
April 14th -- Day to Siena (or more Florence)
April 15th am -- Store bags at Florence SMN Station. Train to Pisa
April 15th pm -- Train via Florence (for bags) to Venice for 3 nights
April 16-17th -- Venice
April 18th, 1PM -- Flight departs.

Take it from someone 47 years old that has traveled solo more often abroad than and with others
It make a difference if you are traveling solo because if you are the captain of a trip (the one whose idea it is the one organizing it) other people can slow your ambition down. That is why i believe what you have put down is doable.

@djp_syd

Thanks for the editions. A few quetions:
(1) I see that you changed Rome # of nights to 4. Leaving for Pompeii on the 10th. I'm assuming this is a morning departure?
If so, wouldn't it be better for me to leave on the night of the 9th?
Actually, I made a mistake. I booked 4 nights, and changed it to 3 a few days ago. So currently I'm supposed to check out on the 9th at 4PM (maybe I can ask the host to extend this by a few hours.).

(2) Is Pompeii chosen due to the ability to store luggage at its strain terminal? I saw this before too, but why set base in Sorrento? I'm aware that Amalfi and Capri are easily accessible from Sorrento, however, I thought a loop (Rome->Salerno->AC->Capri->Sorrento->Pompeii->Naples) may be more efficient?

I've heard so much about Siena from friends as well as people on these and other travel boards. I would definitely visit if not for my desire to go further down South for a few days. Not sure if I'll have time. Not sure if I should spend 3 full days in Florence, or allocate some of that time to Pisa&Siena. If I do go to Pisa and/or Siena, that would leave me with less than 2 days in Florence. I don't actually know what I want to see in Florence yet, but I don't think anything under 2 days is enough.

@Jazz+Travels

Thanks. In your first post, I had thought you implied that it would be harder to do solo than not solo.

Also, I should clarify my OP. I don't know when I'll be able to visit again, but I'm certain I'll make a visit at some time. Probably within the next 10 years. This would be my first time to Italy, and I have an obsession for Roman history, so I'm sure I would jump on the chance to visit again.

My main 2 worries with my itinerary is that (1) Nervous about the 3 day Southern Italy trip.
(2) I think my itinerary is going to be very tiring given all the night traveling that I'm including.

Hey dzdang you are a smart guy go for that southern part and improvise i.e. subtract as needed based on how you feel when you get there. I 've been overly ambitious in my solo travels and that was the result.

@Jazz+Travels
Thanks again. Did you improvise in the middle of your travels?
I'm trying to do that as little as possible given that I'm trying to prebook airbnb housing, trains, attraction tickets, etc...

Hoping my proposed Southern Italy travel works out. It doesn't leave much room for delays/mistakes if I want to hit all those places I mentioned, but I can easily improvise by removing, say, Capri.

Unfortunately Italy is infectious an embarrassment of riches. You can not do all you plan.

Maybe Rome to Sorrento on the train. Book your lodging in Sorrento and use as a base for day trips to Capri and Amalfi.
Cut out Naples and on your way to Florence stop at Pompeii. you are just going to have a back pack for the trip; you know what think about doing laundry every 3 days if you want to really travel light. it is possible.

So I did think about the Rome->Sorrento route originally, but in this scenario, I wouldn't be able to leave Rome at night since the main rails don't connect from Rome->Sorrento (I would have to get off at Naples), and if I take the last train leaving Rome for Naples, there wouldn't be anything available to get me to Sorrento until the morning.

I see this a lot, where people suggest to use Sorrento as a base. What is the benefit of this over moving around like the loop I had proposed? I feel like if I use Sorrento as a base for Capri+Amalfi, the 2 return trips back to Sorrento would kind of be a waste of time?

I was thinking Pompeii&Naples may be doable in half a day each.

Mount Vesuvias sounds extremely attractive as well, especially after watching Spartacus.

Just saw your edits. Do you mean a backpack for the entire 12 day trip or just for the Amalfi, Sorrento, Capri trip?

If it's for the entire 12 days, do you mean a really BIG backpack?
I would need to get a much bigger backpack than the laptop backpack I have currently. I was thinking about bringing my laptop backpack and a small roller suitcase or maybe a duffel bag.

U could do the loop u describe, but it means booking one night stays and then u r committed to a limiting schedule. Also, I don't think u have time for both Capri and Positano/Amalfi (unless u cut Rome back a day).

U could indeed do this but it means an extra hotel and a single night stay.

April 9th eve -- Train from Rome to Naples for 1 night
April 10th am -- Naples
April 10th pm -- Train from Naples to Sorrento for 2 nights
April 11th -- Amalfi Coast (or Isle of Capri)
April 12th am -- Train from Sorrento to Pompeii - store luggage & explore the ruins
April 12th pm -- Train from Pompeii via Naples to Florence for 3 nights

If u spent the 9th as a 4th night in Rome, then an early morning train on the 10th could see u in Naples by 10am, so not really much difference to having been there from the night before.

big back pack for the whole trip that you can carry on.
23 pounds of clothing + toilteries max. skip that if you have to buy it

this is perfect
http://www.ebags.com/hproduct/high-sierra/at7-carry-on-wheeled-backpack-with-removable-daypack/264221?productid=10273059&sourceid=ADWPRODBP&couponid=94790994&utm_source=google&utm_medium=cpc&utm_campaign=Shopping+-+Backpacks+-+Branded&adcampaignid=603478719&adgroup=Backpacks+-+M2&adgroupid=39082844046&addisttype=gpla&gclid=CIums-LeyNICFQi5wAodp2wMzA

Definitely will not cut back anymore on Rome. I'm staying the 3 full days and 3 nights there. I think staying the 4th night and heading south the next morning would cut out more out of my day time, so I think I'm set on leaving on the 4th night, unless there's some drawback to this that I haven't thought of?

If I cut anything out from southern Italy, I'd cut Capri first. Honestly, I only just thought to add that today because I thought it'd be cool to go to an Italian Island.

As for one night stays, that is a drawback monetarily, especially with airbnb, I think, since I have to pay the same service and cleaning fees regardless of the length of stay (I think). But, this is not too big of a deal to pay a few more Euros if it means it's more convenient.

I'm going to look into airbnb housing for my proposed loop. When I thought of this loop, I just thought housing would magically fit in nicely, but maybe that's not the case.

Hmmm, just checked out that backpack. Really expensive.

I don't think I can fit everything in there. It's only about 5 inches longer than the laptop backpack I have http://shop.samsonite.com/business/samsonite-xenon-2-checkpoint-friendly-laptop-backpack/49210XXXX.html.

I have a vague idea of what I want to bring and I can't imagine it fitting in that bag.
I'll bring a few tshirts/polos. A sweater. One jean. 1-2 shorts (I think it'll be warm enough for shorts.).
I also need to bring my macbook.
Toothbrush, toothpaste, sunscreen, Advil, Stomach pain meds (I'm probably going to get stomach aches).
Phone charger, portable battery, phone
Headphones (originally planned on bringing my bigger headset, but if I'm trying to fit everything ina large backpack I can just settle for earpods.)
Towel (I don't know if Airbnb provides towels. This would really save me room if I don't need to bring it).
Toilet paper -- read something about how some public bathrooms may not be equipped with toilet paper.
Camera -- May not bring this due to space and because it's another item of interest to thieves.
Extra pair of shoes -- probably not needed
Water bottle

I did a trip with a similar itinerary 2 years ago. Two comments, take into consideration jet lag and time to change locations at least half day and maybe more depending on distance/ schedule of trains. I see that you have schedule major trains at night which does make things easier if accomendation will let you in either early in morning or late at night. Your pace will slow as you get more tired. On that note, look at cities you want to see and what you want to see in each, consider how long it will take see those things, what would make you satisfied with the trip and what would be nice to do if you have time. Leave a little time open to do the unplanned to sniff the flowers, enjoy a sunset, relax and do impulse item/things that were unplanned -the road less travelled.
As a result, during our trip, We edited out the side trips from Florence and add cinque terra and lost the side trip south, but I must add we walked between 12-20 miles per day. We started and ended in Rome. Rome(arrival only)-Cinque Terra, Venice, Florence and Rome.
As a side note, I must add that the airport for Venice is not inside the city but 40 minutes to 1 hour outside by public transportation.
I will agree that traveling solo means that you will be the driver of the schedule/ itinerary and make it easier to keep the pace needed to do what whatever you want. The question is should you?

One thing to take into account is that you are traveling during Easter week and there may be crowds in Sorrento/Capri/Amalfi Coast. That could mean lines to board buses and ferries. If the seas are rough, the ferries don't go out. Make sure the ferries from Amalfi to Capri are running then, some only start in May, so you'd have to go to Sorrento to change ferries.

It really is your luggage you need to consider - carrying it, and storing it visiting sights. That is why a base is better when u can.

If you do this, you will be carrying your bags every day for 4* days...
4/9* To Naples (1 night)
4/10* To Positano/Amalfi (1 night)
4/11* To Sorrento (1 night)
4/12* Via Pompeii (store bags & visit) to Florence

If you do this, you will be carrying your bags for only 2* days...
4/9 Rome (4th night)
4/10* Via Naples (store bags & visit) to Sorrento (2 nights)
4/11 Positano/Amalfi day trip
4/12* Via Pompeii (store bags & visit) to Florence

Chani is right, accommodation will be difficult over Easter.
(Shout out to Tel Aviv).

Thanks all.

Can I prebook ferries? I'm having a hard time finding the website for ferries.

Here are the sites I use for ferries in the Sorrentine/AC. Ferries run all year from Sorrento to Capri but other schedules - such as Sorrento to Positano - are not up yet as service hasn't yet started for the season.

https://www.capribooking.com/en/ferry-schedule?path_id=21
(note last updates; if it was last fall, boats aren't running yet )

http://www.positano.com/en/ferry-schedule?from=sorrento&to=positano
(same as above: note last updates)

https://www.capribooking.com/en/ferry-schedule?path_id=21
(if a schedule doesn't show at all, the boats are not yet running)

As you're not going during peak season, it's not necessary to book in advance; just buy your tickets at the docks.

Editing to add: there is a note on one of those sites that, "The Sorrento - Positano - Amalfi route usually begins running in mid-May." so I'm unsure just how many routes will be in operation for your dates in April.

You have too many balls currently in the air. For example, ferries should not be your focus at the moment. Priority should run ...
1. Nail down your exact itinerary.
2. Secure accommodation as per 1.
3. Book premium intercity trains as per 1.
4. Flesh out more detailed daily plans with local transport, sights, restaurants, etc.

Thanks. I am trying to secure housing and trains right now.
I'm about to book Naples for one night on the 9th. Then Sorrento for 2 nights.

Great. U r definitely on track then.