If a station's extra space isn't rented out, what's up there other than quarters for the last train's crew? Some of these buildings appear to be fairly large.
Oume, Tokyo-to
https://en.wikipedia.org/wiki/File:JR-Ome_Sta_0803.jpg
Miyoshi, Hiroshima
https://en.wikipedia.org/wiki/File:Miyoshi_station20080211.jpg
old Fukuchiyama Station
https://ja.wikipedia.org/wiki/%E3%83%95%E3%82%A1%E3%82%A4%E3%83%AB:%E7%A6%8F%E7%9F%A5%E5%B1%B1%E9%A7%85%E9%A7%85%E8%88%8E.jpg
more space right next door, the Fukuchiyama branch office
https://ja.wikipedia.org/wiki/%E8%A5%BF%E6%97%A5%E6%9C%AC%E6%97%85%E5%AE%A2%E9%89%84%E9%81%93%E7%A6%8F%E7%9F%A5%E5%B1%B1%E6%94%AF%E7%A4%BE#/media/File:Hukutiyama-sisya,_West_Japan_Railway_Company,_2008-08-15.jpg
I'm sure I could get a decent apartment setup in the Oume building