A random link of the day made me notice that Fujusawa city includes Katase area (same kanji as in the show). The Wikipedia article also lists Machida nearby. Googling further, Kazamatsuri and Kayama are train stations in Odawara city, a little further west.

They are all in it together!

The remaining vaguely Japanese names are Takida, Otoyama, Kusanagi (possible location in Shizuoka, even further south-east), Shirogane, (Ritsuo) Shoujin, and a couple of episodic characters.