Itinerary in Italy

I think it's too much; all those 2 day stops will really result in 1 day or at best 1.5 days for touring; the rest of the time will be spent in travel. With about 12 days on the ground (excluding your arrival and departure days, which aren't of too much touring use), I'd pick 3 places at most, spending about 3 days in each place (assume you'll lose 2 days in travel between destinations). I'd also drop Nice and just focus on Italy, given limited time. I'm assuming you really want Amalfi, given the time you're proposing to spend there. So my suggestion would be fly into Florence or Venice, whichever most interests you Florence or Venice for 3 full days (could take day trip to other city) travel day to Rome Rome for 4 full days travel day to Amalfi Amalfi for 3 full days
fly home from Naples

You don't say what time of year you'll be going, but that itinerary would exhaust me. Generally speaking, you need at least three days each in Venice, Florence and Rome.

I am always of the opinion that if you have to ask, then you already know the answer. However, our first trip (30+ years ago) was like and we were exhausted. It was only after we had our pictures developed did we remember where we had been. Everything was one big blur and we spent so much time in railroad station that a third of the pictures was us on trains. Truthfully, everyone needs one of those trips. Go for it !!! BUT if you really willing to consider a suggestion or two - drop Nice. It is not worth three days or the long flight time from Rome. Two day visits are worthless other than a quick look around. Three are better but just barely. Add a day to Venice and Florence, got to Amalfi after Florence and finish at Rome. You could the five days in Amalfi to rest or cut to four and add to Rome. Come home from Rome.

Thank you Frank. You speak the truth. I agree with you completely. It's just a shame that flights from Rome don't go all the way to San Francisco. Lisa will have to change planes one of the other big European cities or somewhere on the U.S. East coast.
Mid to late morning flights are so much more pleasant out of Rome FCO than their famous 6:00 a.m. flights.

Thanks for all your input. We are looking a the map right now

Alitalia used to fly to SFO (from MXP), just for about 3 years at the turn of the century. They stopped right after Sept 11, 2001. That was a great option for me as well. When I plan travel I like to count nights rather than days. Days are not clearly defined. Do they include transfer/travel time to the next location or are they full day in that location? I don't count the days I travel from hotel location to hotel location. For example I don't count the day traveling from Venice to Florence as a day. At most it's a half day. Therefore 2 nights is one full day in one location, three nights is two full days. My take is: Venice needs 2 nights minimum, 3 if you want to visit the islands (Murano, Burano). Florence needs 3 nights min. Rome is best at 4 nights, including the night before Flying home. Amalfi coast needs 3 nights minimum. If you want to visit Capri, Pompeii, the Coast and maybe Naples or the Vesuvius, you need at least 4. So count your nights on the ground and see how you can allocate them.
I agree it's best to go from Florence straight down to Amalfi, then back track back to Rome for the last few days before the flight home.