Kei's place was excellent and we had an amazing stay. The apartment is in a quiet residential street but can easily access Shinjuku station from the nearby metro stop in 5 mins. The local metro stop is about 10 mins walk away and you have a 7-11 store 3 mins walk and a full supermarket about 8 mins away.
Kei's place is comfortable for 2 people and we had everything we needed to cook and live there for a good few days. Kei was also on hand to help with anything we needed.
We would highly recommend Kei's stay for anyone looking for a well connected base for their stay in Tokyo