Hi I cant fully help but know a little information for you.
There is usually plenty of room to transfer and you usually transfer some of the rides have walkways at the end. So consider if this is a problem, some can be stopped-there is a list in the FAQ (I think)
Some mainstream queues are not accessible by wheelchairs e.g. at MK Splash Mountain, wheelchair users enter via the exit.
At these rides-you need to see the cast member at the entrance to the main queue, you will then be given a card (like a fastpass card with a return time)
Personally im wondering if you can get more than one of these at a time?
We usually do Splash & Big thunder together, so I wonder if we can get a return time for both of these at the same time as theyre the only things we do in that area.
Does anyone know?
Wheelchairs are usually waiting as you get off theride or near the exit.
The cast members are very good at putting them in the right spot and if they recognise you, they'll bring the wheelchair closer if they can.
We've been during the busy times in August and the system has run well.