Katsuo, the host, replies kindly to all questions almost immediately (and in english).
The apartment is conveniently located in a quiet street 5 mn from the KeiKyu Shinbamba station but walking up to the JR Shinagawa station took only 15 mn and can save money if taking the Yamanote line or other JR lines.
Plus, if you like Ramen, there is a lot of shops under the railway when you are approaching to Shinagawa station.