We has the pleasure to stay at Elena's treehouse for 5 days, and we must say we loved it! A beautiful and romantic retreat with great hosts.
Elena and her mother are really kind and make the most for you to feel at home, with great choices of bed linens and towels for the house (and well cleaned treehouse).
Heating works well, and the cooktop and refrigerator cope well with the need for a short and romantic stay.
There is a comment on the car noise, however there is nothing they can do about it, and is a constant distance noise, which ends up in the background, plus you will also hear birds and all, the good side of it, and a fantastic view for sure.
The place is great also to reach Florence (15 to 20 min max.), as well as to explore the chianti region, due to the road access, and the Galluzzo town (ask Elena for the Macellaria address for the best Pecorino and salumi in Italy).
The only aspect, which they could enhance is the blinds, but if you still have problems with light, they are so attentive as to leave two masks for the couple.
Definitely recommend it for a romantic retreat, or even a scape from Florence, really beautiful place and peaceful as well.