3 nights Rome
3 nights Sorrento (day trip to Capri/Pompeii)
1 night Orvieto
2 nights Florence
3 nights Venice
1 night Rome

smiley525,
Consider:
2 nights Orvieto
3 nights Venice
2 nights Florence
3 nights Sorrento
3 nights Rome

A pretty sound itinerary. There is however a pretty good bit of picking up and moving. A lot of people daytrip Orvieto from Rome. Two nights in Florence is really two sleeps and one day of sightseeing, you might want to think about that.

Also flying open jaw (into Rome, but out of Venice) should free up a day.

Yea the flights are already booked the the nights in Rome can't be changed either. I thought it was a lot of moving around as well...

Maybe you could leave directly from Rome to Sorrento, then add your time in Rome at the end so you wouldn't have to stay in Rome 2x?

Also, are you set on Orvieto for any specific reason? Like the other poster said, with 4 nts in ROme, you could do a day trip to Orvieto. We stayed here for one night and found it the least charming of all of the Tuscany/Umbria towns. We stayed in Siena and Assisi and loved both (esp. Siena). Just my $.02 Good Luck!

Well since Rome at the start and finish is a given, I would skip at least one of the other places mentioned. I have no opinion of which one, but for me that would be too much hotel checking-in & out and training (or driving) around for only two weeks time.