One of the reasons we started renting off site was because the wait for a wheelchair at the parks. This is about 6 years ago, but there was only one line to rent wheelchair or scooters. Very busy in the morning. Also if you park hop, you need to perhaps wait again. We did find getting a wheelchair mid day, wasn't busy at all, but still it was another little pause we had to do.
And I second mammbunny about the buses. My DH was the same as you, walking wasn't bad, it was the standing in one place that did him in.
As far as airlines, my DH uses a rollator all the time now. With the plane , he would use it, walk down to the plane and give it to me, I would fold it up. I used some strips of velco to hold it close. After the flight, DH would slowly walk up the ramp, holding onto handrail and then sit at the gate. I would hang out at the bottom of the ramp while the gate agent unloaded the strollers, wheelchairs, etc.
For the past 5 years we had rented wheelchairs off site. I found it also comes in handy when getting a small
walmart grocery order. A case of water fits on the seat perfect. Few things on top, eggs and bread hanging on handles. The wheelchair just became the perfect way to move a few groceries from the lobby to our room. No need to wait for help from bell services.
When we first starting using the wheellchairs, DH refused to use the disabled spots for boarding buses. We just went thru the standard line and when we got up front, just folded the wheelchair and rolled it on like a stroller. If the bus was very busy, we'd wait for another bus. DH needed a spot to sit. That was just our feelings. Not saying you have to do this, just letting you know of the option.
Just another thought, have you thought about getting a folding cane to carry with you. There are rides like HM, that you may need to walk a bit. Or even if you are feeling good, and you think "I'll just walk the line". Partway through, the ride pauses and you may be stuck. The cane may help.
