The cozy little apartment is located less than 5mins walk from Yoyogi station, and short taxi ride from Shinjuku (cost us less than 1000yen). The only inconvenient thing to note is that it is located on 3rd floor, with a steep staircases. Have to be cautious when you have a lot of big luggages and children.
Overall, it is a very pleasant stay with a great host and convenient location! There is a supermarket and convenience stall nearby.