Staying with 2 other friends at Ichimaru's was a great experience. I wish I had stayed 1 or 2 days longer. It is very close to Shinjuku-sanchome station, and it is also walkable from Shinjuku main station. The sofa is extendable to a very comfortable and cozy bed, so this is another option to opt to. The only inconvenience was the small bathroom, but this is how most of Tokyo's bathrooms are like I guess.
Ichimaru is very fast on replying to your questions and is very reachable. Overall liked my stay in this house.