Sorry, you can get the train there:

From Nagoya: https://goo.gl/maps/xRQx9yaSqiF2

From Kyoto: https://goo.gl/maps/mtmcFcWCBAw

From Tokyo: https://goo.gl/maps/7eCsjHuRu6Q2

If you just put it into Google Maps, it will likely suggest a highway bus – these are not accessible.

Would you be ok with a wheelchair taxi while you are there?

Hello,

Aside from Takayama, everything should be fine.  Takayama, on the otherhand will likely be very difficult I believe due to transportation, both getting there and moving around once there…

Does your power wheelchair fold at all?

I can look up specific things if you like, so please tell me what you would like to do and I can check around!

Thank you for the advice @melanie_lmt !

Hello,

Just looking on Yodobashi Camera’s website and they have airmats listed.  https://www.yodobashi.com/category/152022/152200/152335/152341/ (Sorry, in Japanese!)

The Yodobashi Camera in Akihabara is one of the biggest, so I imagine they will have them in the store.