This place is so great! I stayes by myself but I think one other person could also be comfortable there. The space is really new & the bathtub is a bit bigger than normal Japanese tubs, which was nice for my 5'10" self!
I happened to stay here during Typhoon Hagibis & Kawada-san was so kind & helpful, even bringing me food & water before the storm hit since most of the shops nearby were sold out of water. She was reassuring when I was terrified about the typhoon. The building held up through that plus an earthquake so of you're worried about stability for any reason, you don't need to be!
This place is a bit far from the more well-known neighborhoods of Tokyo but there is a robust bus system that can get you to the subways & other rail systems within 20-30 minutes or so.