I stayed at Kouichi’s place for 3 nights with my my three family members, so 4 people in total. It was super comfortable and accessible, although it was a little tight with 4 people. So, I recommend you are very comfortable with the other guests you come with because you will be sleeping close to one another (2 beds and 2 couch-beds fairly close to each other).
Checkin and checkout were both convenient and easy to understand. And I really appreciated Kouichi’s quick response times to any messages I sent.
The closest train station was only about a 10 minute walk away and it was easy to navigate to the rest of Tokyo city from there. I recommend the ¥900 day pass for the metro system.
Finally, there are plenty of restaurants, supermarkets and convenience stores near the apartment so you will never have to worry about going too far to eat.
Thanks for letting us stay and experience Tokyo!