Another option would be to take the train to Florence, rent the car there and spend the rest of the day slowly working your way down SR222 to Siena, perhaps detouring to visit the American (WWII) Cemetery.
Another option would be to take the train to Florence, rent the car there and spend the rest of the day slowly working your way down SR222 to Siena, perhaps detouring to visit the American (WWII) Cemetery.