We just returned from Disney World in Orlando. I don't know if their policies are different from DisneyLand, but this is what we did in Florida.
We went to guest services, got our disabled pass. Basically, it does the same thing as the Fast Pass, but you don't have to go get your "time to return" ticket. You just show up and you go in. Sometimes there is a wait because you're with the Fast Pass people, but not much. I still didn't understand why more people didn't use the Fast Pass lane. Anyway, our next stop was always the clinic. They were fantastic! Faith has to have 1 or 2 therapy sessions while in the park, as well as being hooked up to an IV.
We went at the end of August and it was very hot. So all these things helped. We also found out that she wasn't handling the heat very well, so we got her a wheelchair. That was extremely helpful in getting around the park. Sometimes, the clinic people gave us one, but you are supposed to rent them when you first come into the park. The clinic also stored our portable cooler which had medicine as well as our lunch and some drinks. Every day, we carried 5 bags into the park!!! We did it though and it worked out pretty well. We did everything we wanted to and then some.
Hope this helps.
Carol