We just spent 11 days in Italy in mid-September.
Siena/Tuscany is not to be missed. If you want to get your money's worth there, I cannot say enough good things about two Rick Steve's "finds" there: the first is tour guide Roberto Bechi (www.toursbyroberto.com, whom we hired for a day to show us "hidden Tuscany." He is enthusiastic, has a delightful sense of humor, and knows how to make history come alive. We learned about Etruscans in a way that made 700 BC seem like yesterday, and we saw medieval cities with different eyes than we might otherwise. We "joined" another tour -- it ended up being us and one other couple. That tour was based out of Siena. It was one of the highlights of our trip, and when we return to Italy next year, we plan to hire him for several days to show us some of Italy's other secrets. Another Siena find is the Tuscan Wine School's "Savor Siena" walking tour from food vendor to food vendor -- a foodie's delight that ends with wine tasting at their shop. www.tuscanwineschool.com
We took the high speed Italo train from Florence to Rome, and then the regional train between Florence and Siena and back again, and spent two nights in Siena.
In Florence, we spent one glorious non-museum day (trust me, you need to plan on those or else the art starts dancing in your head!) driving a vintage Fiat 500 through the Chianti wine country, then ended at a lovely villa for another wine tasting. They sent us back to our hotel in cabs. Another lovely, lovely day that we (especially my husband) will never forget! And also a Rick Steves "find" -- highly recommended! www. 500touringclub.com
Be sure to download all of Rick's audio guides -- they really improve the museum experience. And if you have an iPad or smartphone, taking his guidebooks along is super handy. We consulted him heavily on restaurants, and his tip for going straight from the Vatican to St Peter's Basilica was invaluable -- it saved us hours of waiting in line.
Have a wonderful trip!