YK is a really helpful host, with quick responses anytime we had questions. Since none of our group could speak Japanese, he even assisted us in making a reservation in a delicious teppanyaki restaurant close by.
Regarding the flat, there are multiple convenience stores less than 5 minutes walk from the flat, which was awesome. It is also located really close to the Inaricho metro station (Ginza line), so if you purchase the 24 hour unlimited metro pass for 600 yen, travelling around Tokyo is quite cheap and convenient.
The flat came with 3 separate bedrooms with 2 single beds in each room. Beds were comfy and the blankets were really nice and warm (we visited during winter). The only downside is that the bedroom walls don't run all the way up to the ceiling (mentioned in the layout), so you would actually be able to hear each other.
I would definitely give this apartment a hearty thumbs up, for its great location, convenience, and hospitable host.