The house is very neat and clean, also well equipped for families with little kids. As it's pretty new, all facilities and appliances are under very good condition.
It's about 10+ minutes walk from Kanegafuchi station for the elders. There're some 7-11/family mart, bento place, cosmeceuticals and izakayas near the station, so it's relatively convenient and you can explore the local life a little bit.
Henri and Miki are very considerate. They've provided all useful info before my trip. Their responses are incredibly quick.
The only concern was the distance to the railway. For light sleepers, it might not be ideal. But we slept late and got up early, so it wasn't a big problem for us.
Given the average cost to stay in Tokyo, this house is really homy and price-competitive.
Many thanks again!