Had a wonderful 1-night stay at Fujimoto-sou. While the woman who was overseeing things during my stay spoke very little English, she was very accommodating and easy to work with. The room was huge (two rooms!), which just might have been because of their low guest number, and had a beautiful view of the town.
Finding Fujimoto-sou was easy for me with Google Maps, but required walking around the winding streets of Mitake for a bit. The pictures were helpful.
The meals were also fantastic: Creative and definitely focused on the mountain cuisine. Dinner was at 18:00 and breakfast at 07:30, which is fine, because Mitake is quiet. The chestnut wrapped in rice noodles was insanely delicious and unexpected, and featured a small twig of rice-blossoms (this is the only way I can think to describe it). The dining room has a beautiful view of the inn's garden and down the mountain.