I still think my visits to the north east tip of Hokkaido made for an excellent visit, at least to Shiretoko and Akan-Mashu national parks. You fly to Memanbetsu airport from Haneda and rent a car there. Public transit is not a viable alternative however, you need to self-drive. Shiretoko is quite scenic and from the NE side of the Peninsula you can actually see Rissua in the distance. Akan-Mashu national park is one of the few places in Japan where you can learn more about how the folks entering Japan from China way back when treated the native tribes, in this case the Ainu. It's unfortunately very similar to how Native Americans were treated in the USA.