in answer to your question about timing: you do not have to show up 2 hours early in a wheelchair/
ECV. I would show up about 1/2 hour before show to have some choice of where you're seated, but as you can see from Robo's map, all the handicapped seating is at the top.
We were there in mid-May, and I was using an ECV. We did have the Fantasmic seating so daughter & her friend chose to sit lower (not in handicapped seating area with us so they used the F! seating pass to sit about 1/2 way down.) I was parked in one of the ECV/Chair spaces, and hubby was on bench seat next to me. We noticed that the castmembers in charge of that area did not allow anyone (general public) to sit in the handicapped row or the handicapped family row directly in front of it (so basically the top 2 rows) They only allowed family members of handicapped people in the family row...kicked people out over & over before show started...actually had the aisles blocked with a rope, and stopped people from climbing down the benches to get to the seats, too. Even 10 minutes after the show started, people from the standing room only section kept trying to come down & sit in the handicapped area and the castmembers would not let them in (must have heard them tell people 50 times "sorry, this is reserved for handicapped and families." One guy even stood there and argued that obviously no one was using the seats, so why not. Several other castmembers had to join the one that was talking to the guy to get him to back down.) So, anyway, looked like you don't have to show up way early to get the handicapped seating. I suppose there may be times of the year that it is spectacularly busy and maybe all the handicapped areas are taken. But in May, the theater was full, the standing room only was mostly full...but only about 1/2 of the mid to far-right handicapped rows were filled 10 minutes into the show (and no one else showed up late to that area that I could see.)