I can't recommend this place strongly enough! The accommodations are just the right balance between independence and connection, with the ability to cook and a make a home-base for yourself on longer stays, and Kaori san's excellent hosting (and breakfast!) to anchor you in the neighborhood. I spent a little over a week here while in the process of moving to Japan for work, and it was a perfect spot for practically-oriented travel. The apartment is comfortable and well-equipped, in a quiet residential neighborhood.

As others have said, the neighborhood is comfortably accessible, too, with a good hub around the station and other everyday amenities (including an excellent sento, if you're a fan!) within walking distance. It's simple to get to from Narita, and both the subway station (easy access to Shibuya, Shinjuku) and Ikebukuro work well for getting out to the rest of the city.

Kaori san, いろいろお世話になりまして、手伝ってくれたのは本当に感謝しています。成増で心地よく過ごさせていただき、心からありがとうございました！ m(_ _)m