I have rented a house in Vinci (just west of Florence) for a week in June. I'll be there with 5 young adults, ages 16 - 23. I would like to have a dinner at an agritorismo, is it possible to just have dinner at one, or do you have to rent a room? How do I find one?
That policy is set by each property owner. www.viamichelin.com will show you Michelin-reviewed restaurants in that area, including some in rural locations, not all in towns. Here is Ristorante da Delfina near Artimino that I found through the Buon Ricordo site.
If depends if the agritorismo has a public restaurant or not.
We stayed at Castello Di Montegufoni (Montegufoni.eu) just outside of Florence. They had a public restaurant which had a beautiful setting. The food was OK.