Five of us were very comfortable and well treated during our week-long stay. Simona's mother brought us tarts and a basket of fresh vegetables from the garden, and generally looked after us well. The tower really comes into its own on Summer evenings. We sat outside and watched the sun's light fade and the moon rise over the buildings of Sienna. Quite a magical place, particularly when paired with a Brunello.
While not in Sienna proper, it is possible (although not entirely pleasant) to walk to town if necessary, but a bus also services the walled city and the drive to one of many parking lots is quick enough. As noted by others, it's quite easy to launch day trips all over the region.
A note on the house: one bedroom has very low ceilings. It was perfect for our seven year old, but might not be appropriate/comfortable for all sizes. On the other hand, the tower room ceiling soars above four walls of windows. For those travelling in groups but craving privacy, note that the tower bedroom door does not truly close without much fiddling and assistance, due to the stairs below it. Not a problem for us, but worth noting as the room is directly above the dining room.
Well-stocked kitchen and bathrooms, great linens, comfortable beds. We look forward to returning.