Japanese Alps or some of Northern Honshu?

Hello everyone,

I will be visiting Japan for the first time with my partner from the 14th to the 30th of November. He's been to Hiroshima once for a conference and has visited Kyoto, Osaka and the like (but not Tokyo).

A couple of days when we get there and a couple of days before we leave will be dedicated to Tokyo (6 nights - 5 days). So we have about 9 days left to explore other areas. We were thinking either the Japanese Alps or some northern prefecture, or a combination of the two?

What would you suggest? We like hiking (hopefully still possible this time of year in some spots - I saw that Kamikochi closes on the 15th), nature with some historical sights and some good onsens.

I checked the foliage forecast and it looks like it will be a bit later this year: https://www.nippon.com/en/japan-data/h02118/ so what might a good itinerary be to maximise the foliage viewing?

And finally, are there any day trips from Tokyo that would be a must-do because unique, five lakes?

Thanks so much!

For fall colours and hiking maybe look into Izu peninsula.