JRPass

Good stopovers from Kyushu to Hokkaido

Hi,

I have an opportunity to get a great airfare but I have to fly into Fukuoka and depart from Narita. We are thinking about going up to Sapporo since we have never been to Hokaido, with a stop in Osaka ,Kyoto and an overnight in Nikko. Can anyone offer suggestions as to other great places to stop in between. We have already been to Yamaguchi, Hiroshima, Nagasaki, Hakone, Shizuoka, and Mt Fuji areas so we can skip it on this trip. We are also trying to decide whether to do a 14 or 21 day. Thanks!