My MIL used a scooter when we were at Disney (a few years ago). If anyone gave us a dirty look, I didn't even notice. I also had an 18 month old to keep track of, but she let him ride a couple of times (he, he).
Don't worry about what other people think. Do what you need to do.
I don't remember there being a problem with crowds, but this was a week or two before Thanksgiving. Still, people are generally considerate of scooters and strollers, and we had 3 strollers with us.
I thought I remembered most of the attractions having a type of handicap entrance, as there will always be guests who need accommodations. Hopefully you get some good answers here, but I would take the extra time to go to guest services and talk to someone there. They will be able to show you things on the map and talk to you about how to best handle everything.
Take care of your hubby, but try to relax and have fun!!!