Tokyo is expensive everywhere. However, this place has still a moderate price for the size and location.
Liang's house offers two apartments. Both are very similar except that the upper has one room extra (3 sleeping rooms) and the lower a walk-in wardrobe instead (better in case you need only 2 sleeping rooms). The beds in the lower apartment are all single beds but can be moved together to get a big one. In the upper there are two double and one room with two single beds.
The kitchen offers the most important stuff you need to cook. 2 heating plates, microwave and washing machine + tumble dryer included.
The apartments are spacious for Japanese standards including a comfortable living room attached to the kitchen. It's very clean and looks nice. The lower apartment is a little darker inside but it was no problem for us. Lighting is good for all times of day and moods.
The area is very nice and relaxing. It's still Tokyo but close to tolhe southern border to Kawasaki. Tokyo and Yokohama are roughly 30 min by train (Kaikyu line) which leaves at Omorimashi and Umeyashiki (both less than 10 min by foot, connected by local line, you can switch to rapid lines after one station). If you need to buy stuff shops are very close, including a big OK supermarket close to Umeyashiki). Nice little restaurants are close and you'll find much more near Kamata in the south.
It's very calm outside with almost no cars on the road. Children can safely walk outside and you sleep well with just the sound of the crickets from the outside.
Except there are residents in the other apartment. Actually, the fact that the house is only poorly soundproofed is the only negative thing you can say. If the others are not extremely careful and only whispering you can listen the conversations ins the other living room. The sleeping rooms are better because above/below they are at the same position so normally also silent and night. For us it was no problem as it was only loud for maybe 4h in 4 weeks and also the kids slept well.
We loved it to stay in Liang's house (2 weeks in each apartment). The area is surprisingly nice and quite for Tokyo and you have plenty of space. We really felt at home after 4 weeks.