Just an update and also a follow-up to the original post. I decided to spend about four-nights in Nagano (specifically around Yudanaka) for skiing and onsen during New Years. Now my schedule looks like this:

Dec. 27: Arrive afternoon in Hiroshima
Dec. 28-29: Hiroshima/Miyajima
Dec. 30: Leave (morning) for Takayama, arrive early afternoon
Dec. 31: Leave (around noon) for Yudanaka, arrive mid afternoon
Jan.1-3: Yudanaka/Nagano area
Jan 4: Leave (late morning) for Kanazawa, arrive early afternoon
Jan 5-7: Kanazawa/Shirakawa
Jan 7 or 8: Back to Tokyo.

Just a couple of questions. Is the stop in Takayama too rushed? Should I just go straight to Yudanaka and schedule Takayama towards the end? From Takayama to Nagano, I'm planning on taking the train. My friend has said there are buses available but I'm not sure if its a good idea during winter. I think this schedule is OK but I want it to be critiqued/tweaked by more experienced eyes. Thanks again.