I was on the Keys to the Kingdom Tour a number of years ago with two people in wheelchairs. It went very well. They were able to do everything. There is an elevator in Coumbia Harbour House that they used since you have lunch upstairs. I talked to both of the people (we were not with them just meet them on the tour) and they had a great time. I have also done the Backstage Magic and loved it. I can't speak for this tour, but I would think that it would be ok. Disney does a great job. Also I will add that I have done Keys more recently with fibromyalgia. There were places along the way that I was able to sit. I too have trouble at times standing and walking too much. Have fun if and when you do a tour!!
Enjoy The Magic!!