I know europeans take much longer holidays but ours was only 2 days.
We went to mountain area and had great time.
You can see my daughter is soaking her feet in the hot spring water.
It is called "Ashiyu" , meaning "feet water"
It is very relaxing. also we enjoyed hot spring bath at the hotel!
My husband got a little tired after driving 6 or 7 hours but it worth it, I think!