Italy Itinerary?

Hi mmatloff-
Off top of my head?

Fly into Naples, 3 nights in Sorrento, home base for day trips (Should
I spend one night in Naples and one less night in Sorrento)?

3 nights is only 2 FULL days in Sorrento and you'll likely need them both to explore the region so no, I wouldn't spend a night in Naples.

ALL of your other 2-night stays will only give you 1 FULL day at each of those destinations, and Vernazza to Venice, for instance, is a haul that's going to eat up a good chunk of the transfer day

If you only have one FULL day for Florence, you'll eat that up day-tripping Siena and have little-to-no time for Florence itself. If you've previously been to Rome, I'd skip that one altogether and go directly to Florence from Sorrento: 3 nights Florence.

Accommodations in Vernazza could be a challenge to land at this point.. It is a VERY busy summer destination, and any still- available places to stay could be quite pricey. When looking for a room, make sure that it's IN town and not up in the hills or otherwise not within walking distance of the train station. Also look for availability in Monterosso, Riomaggiore or Manarola.

RS tours have the benefit of door-to-door transport that you won't have so every location change you make is going to take you longer. Personal preference but many of us find his suggested itineraries much too rushed but again, it comes down to personal preference.

If you plan to do any museum sightseeing in Florence, you'd need to make sure that the chosen museums are open during the short amount of time you've planned to stay there, and some involve advance, timed-entry reservations.

I agree fully with Kathy and would add that a stop in Rome is unnecessary unless you have a specific reason to do so. Just go from Sorrento to Florence. By doing so you add a full day in Florence.

FWIW, this itinerary awfully fast paced with too much transit time. Perhaps cut Vernazza and add the nights to Venice and Sorrento.

Unless you can fly out of Venice mid to late morning fly into Venice not out of Venice. If you depart on an early morning flight from Venice you will need to take an expensive water taxi (triple digits) to the airport. If you fly mid to late morning out of Venice you can take an inexpensive bus to the airport.
I agree with Kathy and Laurel, skip Rome.
Florence deserves a minimum of three nights and that does not include a day trip to Siena. If you add Siena which you should make it four nights. Buy your ticket for the Uffizi Gallery two-months out to guarantee a reservation.
From Florence’s SM Novella station take a direct train to Salerno: https://www.trenitalia.com/en.html. From Salerno take ferries to Sorrento.
Cinque Terre is the outlier here and you don't have time so skip it.

FWIW, this itinerary awfully fast paced with too much transit time.
Perhaps cut Vernazza and add the nights to Venice and Sorrento.

I'll like Laurel's suggestion: cut Vernazza in favor of more quality time in your other two "water" destinations, or even add one of those nights to Venice and a 4th night to Florence. There's a lot to see in that one (if you are interested in what it has to offer) or choose a day trip in addition to Siena. Going from Florence directly to Venice would cut the amount of time it would otherwise take you by rail from Vernazza by over half, and without the station changes that other journey would involve.

3 nights Sorrento
4 nights Florence
3 nights Venice

Or....

4 nights Sorrento
3 nights Florence
3 nights Venice

I agree with the others. Traveling the length of the country in 10 days is a lot of travel. I would try to limit any transition to 4-5 hrs travel and spend at least three nights in any one region. Chanti (Siena and wine towns and Florence) are easily 4 days. The dolomites and Venice are another 4 days. CT is a couple days add on to Florence and head to Milan to fly home after seeing the Duomo and Last Supper. I would pick a couple regions and leave the rest for the next time. This will be our 3rd trip to Italy and we will see the Lake district and Bologna/Parma as new places plus a couple favorites in 15 days. Next time we will attack the southern region below Roma. Summer is a tough travel season in Italy (and everywhere else for that matter). We did that the first time because of the kids school calendar and will never do it again. Hope you can find lodging and don't let the crowds weigh you down, patience and water will help a lot.

Agree with all above
10 nights is just long enough for 3 locations
Can you add any more nights?

Flying IN to Venice is easier than out of
Venice 3
Florence 3 ( add a night for each planned day trip)
Sorrento 4-it’s going to take most of the day to get here, make it worth the trip

If you fly OUT of Naples later morning/afternoon you can probably spend last night in Sorrento -otherwise spend last night in Naples

Booked air already, into Naples out of Venice.

What time is your departure flight out of Venice?
Getting to VCE for early departures is a pain though not impossible.

Early, 6:30.

Ugh
Any chance of changing the flights??

There are many threads here addressing how to get to VCE early
Do a search and you’ll find them

Honestly I would spend that last night at a hotel near the airport- spend the day in Venice then head to airport after dinner

Double ugh.
I'll second the advice to spend the night prior near the airport. You'll still have to get up at o-dark-thirty but at least you'll be a lot closer and save a little time.

Your flight is going to somewhere in Europe first so getting to VCE about 2 hours preflight is fine

I believe the airport opens at 4 am
No point getting there any earlier than 4:30 or maybe even 5
See if you can find out what time your airline check in desk opens

Read online that water taxi cost 130 euros. Accurate? Didn’t plan on the extra time getting to airport. Worst case, get a hotel by airport. Prefer arrive at airport 2 hours before my flight, 4:30.

Yes that is accurate but there may also be an additional fee for the extra early am pick up

Here is the official site:

https://www.motoscafivenezia.com/en/

There is also the bus option from Piazzale Roma

As I said above - check what time your airlines desk opens
No point getting there before you can check in

The first bus that departs from Piazzale Roma is at 4:20A arriving at the airport at 4:40A. Another thing to consider is getting from your hotel to Piazzale Roma.
Venice deserves three nights not two. Especially if you’re thinking about spending your last night near the airport.

How you allocate time to Florence depends on what you are interested in. Any fascination with Renaissance art warrants a full day to hit a museum or two. We've been to Florence twice, stayed outside the city. First at a campground (we camped for 42 days which was a great way for older visitors to enjoy Europe on a budget); last time, at an agriturismo outside San Gimiagno. Having done a number of trips in Italy from Rome north, I still believe San Gimiagno is the more interesting than Sienna unless you are going to Palio.

If you will be in Venice in July, be sure you are there for the Feast of Redentorre, July 15-16. On the night of July 15, the grand canal fills with boats of all sizes and the night skies crackle with a hours worth of fireworks that reflect in the waters of the basin. I suspect that the celebration of the end of the Black Plague will be quite special this summer. Again, there are many great parties on the planet, including the end of the Tour de France, community events related to the Olympics, NYE in NYC, but I'd be hard pressed to think of one that is more fun than this party in Venice. We figured out that the best way to enjoy was to grab Prosecco and a picnic dinner and find a pleasant place to hang out with newly made friends not far from Piazza San Marco.

To get my brother and his wife to the airport from Venice (we've been there 5 times), we booked a private boat from a hotel on the Lido to the airport. It de-stressed the morning departure and was the classiest way to say good-bye to a wonderful city. We usually are frugal, but ensured our last night together was enjoying all that Venice has to offer.

I’m not comfortable taking the Alilaguna which arrives at 5:10, 6:30 flight. However, I don’t want to spend an exorbitant amount ($150) on private boat. I can spend the day in Venice and leave my bags at hotel and take the Alilaguna in the evening after dinner, stay by airport.

The Alilaguna is not the most pleasant way to get to airport
It will drop you at far end of the airport where you’ll have to walk all the way back to front of terminal to get a taxi to your hotel

Much simpler/cheaper/quicker to take the bus from P Roma to front of terminal

Or consider a land taxi from P Roma directly to your hotel

Last September a taxi from a hotel near the Venice Mestre train station (on the mainland) to the airport cost 35 euros. I assume it would be more expensive from Piazzale Roma in Venice.

I’ve finalized my trip. Hotels booked. I noticed this forum is more friendly than TA.

Fly into Naples/ferry to Sorrento, 3 nights, home base for day trips

Ferry to Naples/train to Vernazza/ 2 nights

Train to Florence/3 nights

Train to Venice/2 nights, hotel near Piazzale Roma/easy access for early morning flight.

Besides museum reservations in Florence, any other advance purchases that I need to consider?

I noticed this forum is more friendly than TA.

We try!

Fly into Naples/ferry to Sorrento, 3 nights, home base for day trips
Ferry to Naples/train to Vernazza/ 2 nights

The ferry is not the most efficient or direct way to get to /from Sorrento, especially if going to Napoli Centrale.
You would need to take taxi to port from airport, then ferry then probably a taxi or bus up into Sorrento. Vice versa for the opposite way. If weather is inclement your ferry may not run.

There is a direct bus from Naples airport to Sorrento.
https://www.curreriviaggi.it/assets/downloads/AUTOLINEE_CURRERI%20dal%201.04.2023P.pdf?t=1680445846

Or take taxi to Napoli Centrale then take the Circumvesuviana to/from from Napoli Centrale to Sorrento station
https://www.positano.com/en/naples-to-sorrento-train-schedule?timetable_route=sorrento_napoli

Scroll down the above link and read all the FAQs

If you are all set on dates- you could buy your train tickets in advance-
https://www.trenitalia.com/content/tcom/en.html

https://www.curreriviaggi.it/en/naples-airport-shuttle

Question, on my return to Naples from Sorrento, onward to Vernazza, make more sense to take the train, Circumvesuviana, reviews are terrible or take this shuttle back to the Naples airport and take a taxi to the train station.

That depends on what your comfort level. I like the Circumvesuviana train when not transporting luggage because no one pays attention to you. If I had bags to keep track of that could be tricky.
You’re traveling to an area with high unemployment and a lot of locals ride this rail. If you pack heavy and are carrying a lot then no. If you pack light and don’t have a lot of baggage to hold on to then you should be OK.
I took a ferry from Sorrento to Naples and a taxi to the train station.