We had a wonderful stay in Florence in Carla's villa. The house (with high ceilings and lots of art) and the property are extremely beautiful and made for a unique experience. There were some mosquitos, due to the large garden, but it was still OK.
The house is located in the hills not too far from the city center. One day we took a nice walk to the center, the other times we took the bus, which worked quite well for us.
Carla really went out of her way to make our experience a great one: she picked us up from the bus station one night, reserved a restaurant for us, gave us lots of good recommendations, and was generally fun to talk to.
We also had a great special dinner (on my birthday) at Stefano's Restaurant, which we would highly recommend as well.