Going FROM the airport to your room won't be a problem, except for time. Busses show up at the airport every few minutes. You just wait till they provide a bus with a lift.
Going TO the airport from your resort can potentially be more problematic. I would request an earlier pickup time than they suggest to allow time for them to send the correct type bus. (Just in case they send the wrong type bus the first time). Just make sure you tell them at every opportunity that you MUST have a lift bus.
When you make your reservation, tell them you need a lift bus.
When your tags come in the mail, call and confirm a lift bus.
When you arrive at the Magical Express Desk, confirm that you need a lift bus for your return.
When your return time ticket shows up on your resort door, drop by the resort desk and remind them you need a lift bus and change the pickup time to one hour earlier.
You probably will have no problems, but just take the above precautions to make sure.