Nakano has become very popular with locals and tourists alike in the last few years, and you won't run our of food and entertainment options. The flat is close to many of them, including a convenience store.
The place is small but it has everything you need. The washing machine is coin operated and on the floor below. It is not possible to take a bath. Any sounds made in the bathroom can be heard in the whole place.
We thought the single futon with no mat arrangement was too hard for our liking, but we told the host and an extra futon was provided.
The only issue is the karaoke in front of the building, you'll hear people sing and tambourines, and the street can get pretty loud when people leave at the early hours of the morning, even on weekdays. Didn't really bother me, and a pair of Hello Kitty earplugs solved the issue for my wife.