21 days in Japan

Hello,
My wife and I are travelling from NZ to Japan in June 2016 - we are in Japan for a total of 20 days.

1) We arrive in Tokyo Narita Airport and will then be travelling to Shin-Urayasu to spend 4 days at Disney and Disney Sea. Will we be able to use the pass straight away to get to our accom by train or bus?
2) Travel back to train station in Tokyo for next leg?
3) Tokyo to Nagoya (3 days in Nagoya)
4) Nagoya to Osaka (3 days in Osaka)
5) Osaka back to Nagoya (3 more days)
6) Nagoya back to Tokyo (4 more days)
7) then out to airport to travel back home

Do you think all of these trips would justify a 21 day pass? considering that I imagine we will use buses and trains while visiting these various cities as well.
Any help appreciated.
Warm Regards