I would spend most of my time in the Amalfi Coast and Tuscany, more specifically Montalcino. Siena is great but it's well-suited for a day trip. There are a bunch of wineries that have accommodations and I highly recommend staying at a vineyard. It was one of my highlights of my trip. Also, buy more wine than you think is necessary and ship it back the the U.S. Regardless of how much I buy I always wish I had bought more 6 months later.