We stayed three nights at Kaori's place and had a comfortable stay. Kaori met us at the station even though we were very late and she had to be somewhere else!
The apartment is in a quiet, pretty neighbourhood. It is a 2-3 minute walk away from Narimasu station and about 25 min (¥410) to Shinjuku station and 30-35 min (¥420) to Shibuya station.
We enjoyed the lovely breakfasts that Kaori prepared for us each morning and the opportunity to chat with her and see the art being exhibited in the cafe.
Overall, a good place to stay if you're looking for a private apartment in Tokyo.