My 15 yo old daughter is really wanting to visit Volterra to see all of the Twilight/New Moon locations. We will be staying in Florence. What is the easiest and fastest (doesn't have to be the cheapest) way for us to get to Volterra?
Public transport is not great for a same-day roundtrip. A bus runs about 4x/day (Mon-Sat) from Florence's bus station and takes two hours each way, with a connection. Starting out by train takes longer and still requires a bus connection. Instead, consider car rental, a scheduled tour, or a private chauffer service such as PrestigeRent.
A scheduled tour would be great but I'm having a hard time finding one. Do you know of any?
Your daughter bring a Twilight fan might want to visit Montepulciano where the Volterra scenes were filmed.. I love both those hill towns.
The scene your daughter is talking about was filmed in Montepulciano in the Piazza Grande. We (my husband and two teen daughters and I) just got back from Italy and visited both Montepulciano and Volterra - both are stunning Tuscan towns with their own personalities and we enjoyed them both! Check out this link for more details on where the Twilight movie was filmed:
http://www.movie-locations.com/movies/t/Twilight_New_Moon.html#.VbPxtob3arU
Whether you go to Volterra or Montepulciano, or both, I would go by car.