In Japan for 3 weeks but lots of areas + a week of skiing...

Hi

I'm planning on visiting Japan next week (for 2.5 weeks) and I'm trying to work out if it is economical to buy the full JR pass for the entire time considering there will be 6 days of skiing and not using the pass to its full potential... or to split passes according to area...

My rough itinerary is as follows:
Day one: arrive in Osaka
Day two: Day trip from Osaka to Hiroshima
Day three: around Osaka
Day 4-6: Travel to Kyoto for 2 nights (from Osaka)
Day 7: travel from Kyoto to Haukba (I think this might be via Tokyo then up to the alps)
Day 7-15: Skiiing in Hakuba
Day 16: travel fro Hakuba to Tokyo
Day 16 - 20: Stay around Tokyo and day trip to Mount Fuji

I wonder whether it would be worth getting a regional pass for the first 5 days and then paying separately to get up to Hakuba and then buying the the full JR pass for the last 7 days?

Any advice would be much appreciated!