Well...here it goes. I am a little nervous, but I am looking for some suggestions.
Day 1 Arrive in Venice
Day 2 Venice
Day 3 Train to Cinque Terre
Day 4 Cinque Terre
Day 5 Train to Florence
Day 6 Florence
Day 7 Florence with day trip to Siena
Day 8 Train to Sorrento
Day 9 Sorrento
Day 10 Sorrento/Capri
Day 11 Train to Rome
Day 12 Rome
Day 13 Rome
Day 14 Fly Home

I am not sure...but we might do Florence before Cinque Terre bc of lengths of train runs?? Also, should we stay at Monterosso or Santa Marg. Ligure?

Your itinerary is too hurried, with too many stops and not enough time at each stop. Look at the high ratio of train days to the overall trip for instance - valuable enjoyment time lost.

Do some editing, save some of the goodies for another trip. To savor the goodies of this one, you must linger a bit - soak it in - and not have to rush off to a train connection.

I agree, your trip is just too hectic. As has often been recommended on this board, think about choosing Rome and south or Rome and north and saving the other for another trip. I'm partial to Rome and north but, depending on when you plan to travel, you may want to go south. In any case, you need more time to enjoy the moment and less time running for trains.

With your time--really closer to 12 days of tourism--I would not do more than 4 destinations. In this case, drop one of the coast destinations.

Once again I agree with expert bobthe.

Reluctantly I agree, skip either CT or Sorrento/Capri, have your scenery in one place but not two, just because of time constraints and too much rushing about. Currently you have 2 days in Venice (one presumably being jet-lagged), the remains of a travel day plus one full day in CT--that alone is way too much travel for such a short stay. And what if it rains that one day?

This discussion came up recently and some prefer to end with hectic Rome, but if I could choose I'd start with Rome and end with Venice, La Serenissima (the most serene one).

We just returned on a trip where we did Venice- 2 days, Tuscany- 3 days (picked up car in Florence but didn't stay to tour the city), Cinque Terre- 3 days and then back to Florence- 1 day. I would recommend doing Florence in the middle because it is in between the Cinque and Venice, about a 3 hour train ride from Venice. Plus, we did not particularly care for Florence because it was such a big bustling city with cars and mopeds after being in much quieter places with hardly any cars at all.

We did not have as much time as you (9 days) but we also had fewer destinations and I wish we had stayed a little longer in each place. Keep in mind how much time it takes to train and travel to each place- longer than I had anticipated in my planning.