2 weeks Japan in Dec/Jan: Tokyo and ?

Planning 2 weeks trip in Japan from 12/24-1/5. We have been to Japan many times and it's usually Tokyo + 5-7 days of something else, such as (places we've been to) Hokkaido, Osaka/Kyoto, Niko, Kamakuro, etc..

Any recommendations on where to go besides Tokyo around this time of the year? For example, we have never been to Kyushu...or Okinawa. Should we? What to do around this year? Note that we are travelling with kids (5/10 years old) so any extreme hiking probably not for us.

You could check out Tohoku. Sendai, Matsushima, the fox village...

So many places to visit. Just restricted due to winter. Considering the kids. Another time of year opens up so many other oppotunities in all areas of Japan.

Okinawa is popular during the winter and won't be limited due to weather. Not your classic winter experience, though. I'd give it a try if you can get a decent deal.