Hi there,
Tokyo - Osaka - Kyoto - Tokyo is a bit of a classic but it's the best for a first time trip to Japan as you get to see both the traditional side and modern parts of Japan. A 7 day Japan Rail Pass will help you here as well, the cost of the pass is about the same as a normal return ticket Tokyo - Kyoto using the Shinkansen, after that, you can consider any additional travel free. Whether you should spend more time in Osaka or Kyoto is a personal thing, are you more interested in the metropolis life of Japan or the more traditional. Tokyo and Osaka are both the former, while Kyoto is the traditional capital of Japan. Since you already spend a good amount of Tokyo, it might be nicer to take more days to enjoy Kyoto after but that's just my suggestion.
For snowboarding or skiing, my best suggestion is to do a day from Tokyo to the snow resort town called Gala Yuzawa. You can use the JR Pass there to be in under 90 minutes, enjoy all the snow fun you'd like and be back on the Shinkansen once dark sets in.
Hope this helps,
Daniel