Hatouchi Pass a mountain pass that leads from Iida city to Odairajuku. The surface is gravel, sand, and rocks. In Odairajuku there is a restaurant and guesthouse called Marusan. Try the goheimochi. They are delicious.
Guides and rental bicycles are provided by ABC (Alps Boken Club). The pass can be walked in a couple of hours. You should check the opening hours of Marusan, so you can buy refreshments and gohei mochi once you are up there.