First of all, Ylenia is delightful and has everything ready for you to have a great experience in Firenze! Her flat is in a neighborhood just outside the city wall and with a bakery across the street and produce stands up and down the street you can live like a "local" if you want to. It is a 20 minute steady walk to Piazza della Repubblica or the Ponte Vecchio, a 15 minute walk to Firenze SMN train station, and 25 minutes walking to the Duomo with lots of Gelato and shops along the way. Florence is a beautiful city in the middle of everything so we used the flat as our base of operations, taking an overnight to Rome and many day trips into Tuscany and to the coast. There were 5 of us, aged 18 to 56, and the flat was the perfect balance of value, space, and convenient location. It is just far enough out and on the "other side" of the Arno that there are nearly no tourists other than those in the flat with you. If you are going to Florence be ready to walk. A lot. On stone sidewalks and cobblestone streets.
Ylenia's place was a perfect fit for us.