Ok, so just book it. There really isn't a homestay in Cambridge better. I found Tanya after another AirBnB host cancelled at the last minute, and I am so glad I did, especially since I stayed for nearly 2 weeks. It's ridiculously well-located for Harvard, the room is spacious and yet cozy (very Cambridge), there was great AC, coffee in the rooms, chocolates, OJ, etc. The room is beautiful, and the house is gorgeous. There is a bathroom that only I used, with great shower pressure, shampoo and soap, etc. It was quiet, the mattress was great, the bedding was high quality, and it was so easy to turn off the lights in the room from bed (which was surprisingly awesome.) Tanya and her family were friendly but not intrusive in any way, and there to help, loaning me an umbrella and delivering something I forgot there right after I left. I had weird hours, and it wasn't a problem. Tanya is warm and great at communication, and responded within minutes of every email I sent her. I've probably done a dozen homestay AirBnB's and this was the best one!