2nd time in Japan, looking for itinerary advice outside of Kyoto, Osaka etc

2nd time in Japan this September. We have a great time the last time we went but we did all of the major tourist stuff and don't feel a need to get back to Kyoto. We are flying into Tokyo and know we want to spend 1 week there, but looking for some ideas for the remaining week. From our last trip I remember wanting to see some smaller towns than the massive megacities and we definitely needed some more downtime on the last trip so it would be good to build that in as well.

Ideally we don't want to take any more flights once we're in Japan so that would rule out Hokkaido and Okinawa. We thought Kyushu might be too hot in September was was thinking about maybe a road trip up to Kanazawa or maybe through Tohoku.

Any suggestions or ideas on how to fill a week?