We recently stayed here with 12 family members for a week. Although it is a little off the beatn path and not easily accessible to the train station, Filippo is wonderful. He is the top contact for having a driver available. Be sure to email him and make arrangements. He is VERY knowlegable and very reasonable.
We went to several towns, spent anywhere from 2-4 hours in each. Plenty of time.
Make sure you hire the chef for at least one meal. She is amazing. We had a 5 course meal that lasted several hours. My suggestion, maybe not the first night like we did because we were so tired, but it worked out very well in the end. The food was delicious!!!!
The villa is a nice set up. Nice areas to spend time together and yet everyone has a room to go to at night.
Another suggestion is to go grocery store before the Villa so that you have some basic needs. Coffee, Water, drinks and things like that. There is a local close store. The meats and cheeses are a great idea...