I was in Hokkaido last December, and although no DSLR with me then, I think the conditions may not exactly be that bad for a DSLR. Just bring extra batts, and make sure you do daily maintenance with your camera. It can get wet quite easily when it starts to snow.
Also, don't be too overly protective about the camera. If it is a holiday right, just enjoy it. Precautions like take out only when necessary is pragmatic, but it depend on your preference.