We stayed (5 adults) for 18 days at Elizabeth's place, casa Harmony, and it was great. Everything announced here is accurate: great location, nice and spacious house (for Japanese standards), fully equipped, portable Wi-Fi and quiet and friendly neighbors.
If you are in a group and want to know the real Tokyo this is the right place to stay.
Elizabeth, the owner, is a very nice person and you can depend on her to give you usefull tips.
Thank you Elizabeth for a great Tokyo experience.