The best way to see a lot of Tuscany cheaply and quickly is by using the very reliable TrenItalia services.
First class tickets are only a fraction more expensive and you get a glimpse of another side of life in Italy. The best bit is that everyone talks to everyone, whether they know each other or not!
Booking gets you in during the busy season. Sometimes you can arrive and do not need to use the reservations line so forget to mention the booking and save 3 Euros per person. Avoid June and try the winter period for a calmer visit.
They speak English and are helpful.
Send your feedback or queries to firstname.lastname@example.org