Work is taking me to Tokyo the first week in October. Wife and 9yr old daughter will join me in Osaka and we plan of visiting it and Kyoto. We’d love to go to one more place in Japan (we spent a week in Tokyo and surrounding areas last year) There seem to be an endless number of fantastic sounding places we could go. Any suggestions come to mind, especially given the time of the year, and where we will be?

Is Hokkaido too ambitious with 3-4 days and the recent earthquake? Nagasaki?

Thanks in advance!