1st timer 7 days itin check

hi, im planing to visit japan on early december. for 7 days.
my planing is like this :
day 1. narita-tokyo, explore tokyo.
day 2. universal whole day. or if still have time will continue explore tokyo.
day 3. ski. this is my biggest problem. is gala yuzawa (niigita) or yamagata already open early december?
day 4-6 day4 early train to kyoto and explore 2 day? (is it enough 1 day?)
day 6-7 osaka, and take 8pm flight going home from osaka

or maybe have another better option?
thx