What is a Shukubo 宿坊?
Simple answer, temple lodging.
Some temples in Japan offer temple lodging, most famously in Koyashan - at least to foreigners.
But there are others too. Zenkoji, 3 mountains of Dewa in Tohoku, also in Shikoku for the Henro, etc (even a few in Kyoto!)
Around Zenkoji there...