Japan has some of the best roads for road biking in the world, but these locations are far from Tokyo.
Robert McManmon runs a bike tour business, They rent bikes and do guided tours which cover the Gunma Prefecture and the Tochigi Prefecture be sure to check them out: https://biketourjapan.com/
The plans changed because of bad weather but with a quick look at the weather map they were able to find a great sunny spot for a ride, which shows the flexibility a camper gives you.
If you want to rent a bike rack with your van let us know.
Locations featured in the video:
Mt Akagi and hiking near caldera lake
Elevated wooden pathways: Kakumanbuchi Marsh
Lake Umeda just outside of Kiryu
Akagi Miyozawa Shrine
Echigo-Tsumari Art Town