With Kids in Oct: Japanese alps or Hokkaido?

We are unable to decide between two destinations for our third trip to Japan in October: Japan alps or Hokkaido? We have 8 days. Our kids are 7 & 9. We have done Kyoto, Nara, koyasan, Tokyo, hakone circuits before.

Considerations: Alps: we were considering Tsumago-Magome hike, couple of nights in a farmhouse in Shirakawago, and then on to Takayama, Kanazawa. We want to keep things at slow pace. Our kids have done hikes in HK - we just slow down the pace and take a lot of breaks

Hokkaido: we would possibly rent a car and drive around the standard destinations starting Hakodate or Sapporo, on to Furano, lake Akan, etc.

We will throw in free time for kids at each location.

My question is, since both destinations have all outdoor things, is the weather in mid- oct an issue? Hokkaido ranges from 7 to 16 I read but if it rains that can be uncomfortable. I don't get much info on what the climate in alps wd be around that time. Also, are there other regions worth considering over these two? Any suggestions?

Season-wise, mid Oct is a good time for autumn foliage in Hokkaido.
http://www.japan-guide.com/e/e2014_when.html

If you can, arrange to fly open-jaw by flying into Asahikawa and work yourself south flying out from Hakodate. By the time you reach Hakodate koyo would hopefully follow you as it is said to be a bit later than the central part of Hokkaido.

In Asahikawa you can do a daytrip to Sounkyo which is a very popular koyo destination in Hokkaido. For the kids the Asahiyawa Zoo would be a fun place. Also in Asahikawa you can taste the best Hokkaido ramen in the Ramen Mura.

Furano during Oct maybe a bit barren, so if time is limited skip Furano and go further south of Sapporo. Jozenkei and the Hokeikyou Dam area is another popular koyo destination. Enjoy an onsen experience in Toya-ko with the added bonus of daily evening firework event and also a side-trip to the Hell Valley in Noboribetsu. In Hakodate don't forget nearby Onuma Park which is another popular site for maple colour.