We had a lovely stay, in Stella's apartment. It is well located in a quiet road but with easy access to the tourist places and a handy supermarket, The place is very clean and well equipped.
There are some fabulous parks and walks on the south side of the river where the apartment is. I'd particularly recommend the Boboli gardens. You can also get a bus direct to Siena from the end of the street but do buy a ticket beforehand from the bus station. Stella was very friendly and welcoming too.