Need help for planning a trip to Italy

If you do not yet have a guide book, get one.

What you outline is 'doable' but not the way I would allocate my time. That is a subjective choice, based on what YOU want to do with your time.

I would distribute your time in each place differently but it is up to you. I would spend less time in Amalfi Coast.

If these are the places you're really interested in, then yes, it's doable. I would also allocate the days differently, giving one of your Amalfi days to Rome. Consider that your first day in Rome, if you are coming from North America, will be pretty much a jet lagged blur. I would also recommend that you look at getting a multicity (open jaw) ticket into Rome and back from Naples. This will eliminate a wasted day getting back to Rome the night before your flight home.

If a return ticket to Rome turns out to be the only choice, then consider doing your Rome stay last. Go to Florence right after landing in Rome. Then go to the AC, and finish in Rome.

As previous posters have suggested, I would also divide my time differently, but let me explain why your goals can make a difference. When I travel ( and Italy is my favorite destination), I am a real sightseer. Churches, museums, historical sights, architecture, as well as little back streets and alleys are what I want to see. Beaches to me are pretty to look at, but I don't need to go swimming or spend time laying in the sun. If you want to spend some of your time just relaxing on the coast, then your itinerary might be best for you.

For me, four days in Amalfi would be plenty, and I did love that area. I could spend six days in Rome easily, and then one day in the hill town Orvieto on the way to Florence to finish the trip.

FYI, a year ahead is not "early" -- some would say it's "just right." If you plan on using airline miles for a free flight, the reservations open up at about 11 months out.
I LOVE Sorrento/Pompeii/Amalfi area for relaxing downtime and beautiful views, but would cut back some (3-4) of your 7 days to spend more time in Rome and Florence, especially on a first trip.

I plan most of my big trips at least a year in advance. Sometimes more... ;-)

As far as how you spend your time, I agree with the above posters. If I were trying to figure out how many days to spend in each place, I'd start off by making a list of what I wanted most to see/do in those locations. Rank them in some order. I often use

-HAVE TO SEE/DO this
-Really want to see/do this
-This would be cool if there is time...
-I could live without seeing this until maybe next time...

See if one area has FAR more 'HAVE to see this' items. That will tell you where you want to spend most of your time.

Don't forget to book in travel time from one city to the next, too!

Something else important that I learned and follow from the experience on this forum is to look at how many nights you have, not days. You write you'll be spending 2 weeks (14 nights, including or excluding travel?), then the days you list add up to 14 days. Think of 3 nights as 2 days, etc., and also that arrival and departure days don't really amount to much. That helps with figuring out how much time you really have on the ground for what you want to do. Have fun!

I just wanted to add to what aquamarinesteph posted: for each location include a "do this if it rains" plan, just in case.

If you have 2 weeks then my guess is you have 12 nights in Italy and 2 travel days. one on each end. My suggestion would be to fly into Naples and go right to Sorrento. Technically it is not on the Amalfi coast but it's a great place to base. Sorrento is bigger than Positano with more restaurants etc, From Sorrento you can ferry to Capri, ferry to Positano and take the local train to Pompei. Stay 5 nights. That will give you 4 full days. and a half day the day you arrive. Then take the train from Naples to Florence for 3 nights. That will give you 2.5 days. Train from Florence to Rome for 4 nights which will give you 3.5 days and fly home from Rome.

I just went for 15 days in July and would like to share my intinerary with you. We landed in Venice and stayed for 3 days.
From Venice we took the train to CInque Terre. I had been to Amalfi and Positano before and always had Cinque Terre on my bucket list. I much more preferred that area. It has a much nicer charm than the other 2 in my opinion. I stayed in Monterosso at Hotel Porta Roca. The beach was spectacular there and the other islands are easily visited by a 2 minute train ride or hiking. We stayed there for 4 days. (wish it was longer_
From there, we took the train to Rome and stayed at Albergo Del Senato right across from Parthenon. We did a day tour to
Tuscany from Rome as well. We stayed here 4 days. My husband had never been to Capri so the easiest way to see that area
was to do a tour. I did a 3 day tour thru Viator (which I usually don't like doing) but it took us to Naples, Pompeii and Sorrento.
From Sorrento, they took us for a full day in Capri which was wonderful.
So yes, I did not see Florence or Positano but I feel it was a great trade off doing Venice and Cinque Terre. Flew home from Rome.

I just did that trip in July. I will give you our itinerary and then my thoughts on our choices:

Itinerary:
Flew into Florence and spent 2 nights there. Did a walking tour one day and a cooking class in the outskirts of Florence the next.
Took a driver down to a castello in the Chianti region and stayed in Tuscany for 4 nights. Did day trips from there, including San Gimingnano, Volterra, Siena, Montelcino and Montelpulciano. Did wine tasting in Montelcino and Montelpulciano.
Took a driver back to Florence and took the high speed train down to Salerno.
Took a ferry to Amalfi and stayed there for 4 nights. Rented a boat and captain one day and did a trip to Capri. Took the ferry at night to Positano and the hotel shuttle to Amalfi for dinners. Took a taxi one night to Ravello for dinner.
Took the ferry back to Salerno and then took the train up to Rome.
Had dinner in Rome and left the next morning for home.

My overall thoughts:
In general we were very happy with the itinerary. We could have used an extra day in Florence though. We really liked it and felt like we had to leave too soon. We were very happy with our walking tour and I would highly recommend Paul Costa of Tuscantourguide. Very informative and interesting. We are not "tour" type people and really enjoyed this.
We thought Tuscany was beautiful but we did wwwaaayyy too much driving around between towns. I enjoyed them but getting to and from was tiring and made us nauseous driving around all those curvy roads (and we had a driver). We also did some of it on purpose because we wanted to learn about Italian wine so it was kind of necessary for us to try wines in the different areas. Unless you really love sightseeing in those small towns though, I would limit it to a couple. Our favorites were Volterra and Siena. I would recommend Siena in the evening since it's really pretty at that time and has a fun nightlife. I would even consider staying in Siena next time rather than the countryside. That brings me to our other issue - our castello was crazy quiet. I'm sure many people like that, but for us it was almost too quiet to be comfortable. It was beautiful so I would recommend it if you want that type of peace and quiet, but for us we could have used something more lively.

We absolutely loved amalfi and would probably dedicate more time there on our next trip. I highly recommend the hotel we stayed at, Santa Caterina, but it was a splurge for us, so it wouldn't necessarily be in my budget next time. We said next time we would like to spend some nights on Capri and then some in Amalfi. The ferry was a great way to get around - very happy we did that. Especially after leaving Tuscany and all the windy roads. Amalfi is similar - all the roads are narrow and winding.

We didn't spend much time in Rome so I can't speak to that much, but since you have more days than we did, I would definitely recommend spending a few there at the end of your trip.

A couple additional suggestions if you have extra time would be Naples, Pompeii and near Florence I'd recommend Lucca and Pisa. Cinque Terre might be nice in September. I'd like to visit there as well but couldn't fit it in our trip this last time.

Hope this was helpful. Happy to give you more specific advice or suggestions if you need it. Have fun!

I like villages better than large cities. I like to plan one large city and the rest of my time in smaller villages. i don't like to stay less than 4 nights in any one place as too much moving around is tiring and you lose sightseeing time on a travel day. On a two week trip, with the two travel days for going and coming, that leaves 12 days to see Italy. I would pick no more than 3 places to base out of and do day trips from your base city.

As others previously weighed in, how much time in each place depends on your interests? For instance, we've no interest in beach time but can't get enough of the art, architecture and history in Italy. We've enjoyed some smaller corners versus larger cities as well as some of the coastal landscapes. That said, I'd opt for trimming down your time in the Amalfi area for adding a day to both Florence and Rome. There are some really nice day trips from Florence - which is a fascinating city all by itself - and Rome takes a bit of time to wrap one's head around: lots to take in there if those things trip your trigger.
Counting number of nights you'll have on the ground in Italy will give you a more realistic overview of how much time you really have to work with.

I'll gently disagree with Dina that "the easiest way to see" the Amalfi area is with a tour. It's really not a difficult place to explore independently (we have) with a little reading in advance and some questions here on the forum. You can take ferries from Sorrento to Capri and some other locations around the coast, and there's SITA bus service around the coast as well: if your stomach can take the winding roads, combine buses with ferry transport as boat runs can be a little limited and are more expensive. Pompei is easily done by very cheap commuter train from Sorrento: takes about 30 minutes. Travelers with more $$ than others sometimes hire private drivers for a day to Positano, Amalfi. etc.