Our host Hiro-san was very responsive to all our enquiries and gave us tips on transportation and places of interest. The apartment - 2 units to be exact, were cosy and well-equipped. It is about a 5 min walk to the nearest subway station - depends on how fast you walk. To Shinjuku proper - Isetan junction would take about 20 - 25 mins but a pleasant walk.
Lots of restaurants and convenience stores nearby. The place is quiet despite being just off the main road. The Shinjuku Gyoen Garden is nearby too. A nice garden to spend some time exploring.
I would recommend Hiro-san place for a cosy stay.