The house is located very close to public transport (less than 5 minutes from Shin Otsuka station of Marunouchi line and about 10 minutes from Otsuka station for Yamanote line if you're using JR pass), and it's also within walking distance from the lively Ikebukuro. You can also find a lot of convenience stores, a 24 hour supermarket, and a coin laundry nearby; it's very convenient. Despite that, the location is secluded enough so that you can still enjoy a peaceful rest at night.
Not only that, the room is very comfortable. You'll have your own mini pantry (stove and sink) in your room, and you can find the fridge and microwave on the corridor. Oh, and the blanket is super warm and fluffy, which is always a plus.
The Oie family is also very warm. I had a great time chatting with them and they made me feel really welcomed. They are eager to find out about new things from their guests. They also gave me tips on where locals go for sakura viewing which you would unlikely find online.
All in all, I had a really great time staying at the Oie house and would totally recommend it. I'd love to stay there again if I visit Tokyo again.