Sorry for an unprompted response, but if you’re enjoying cycling and willing to do detours, I’d suggest to check out cycling routes themselves. There are some amazing designated roads that are insanely nice and fun to ride when the weather is around 15-25c.
Shiamani Kaido is the most famous one. Gorgeous views across little islands and bridges. Lake Biwa course is easier, and it’s neat during fall. There are a bunch of japanese cycling route websites if you wanna go through big list of possibilities.
There’s a bunch within Tokyo area as well, but obviously different vibes.
