Just moved the thread over to our Guests with Special Needs forum, where there are many experts who can help!

For us, we've travelled once with my Mom who needs and ECV, and we rented it from an off-site company (Buena Vista Scooters) and were delighted. It was great to have it for her to explore the resort, as well as for getting to the park itself.

We had an experience a couple of trips ago, where I hurt my back and needed a wheelchair for a couple of days. We just rented them from the park, but again, found getting from the car/bus to the park entrance was hard.

In both cases, Disney is great for those in ECV's and wheelchairs. For most things, such as the shows, you can stay in it, and for the things where you need to transfer, they will make sure you have the time you need, and will have your ECV or wheelchair waiting for you when you get off.

I would rent one from an off-site company, so you know you have it for the entire trip.