What you want to do is gate check the wheelchair. That way, you can keep it with you until you board (wheel it right up to the door of the plane) and it will be delivered to the gate for you when you arrive in Orlando. That's a good idea because it's a loooonnnnggg walk from the gates at Orlando to the terminal, even if you don't have to stop to pick up your baggage.
If she can walk, you don't need the aisle chair that is mentioned on the website that a link was posted to.
Tell them when you check in that you have a wheelchair that you want to gate check. Sometimes they will give you a gate check tag right then. More often, they will tell you to get one from the gate agent. It's important to get one as soon as the gate agent arrives at the gate (don't wait until boarding), make sure it is filled out correctly (sometimes there is a choice of having the wheelchair delivered to the gate or to baggage claim) and is attached securely to the chair (if possible somewhere other than the push handles, where it might slide off the edge of the handles, or slide it down a bit on the push handles).
There is also a piece of the gate check tag for you to tear off and keep - that is your baggage claim and is your proof that they have your wheelchair, so it's important to have. You leave the wheelchair at the gate and the baggage handlers will take care of it. If there are any removable pieces (footrests, armrests, cup holders, etc), it's best to remove them. Then fold up the chair beffore you leave it.
If you haven't arranged for gate checking before they start boarding, it's easier for the gate agent to make a mistake and the wheelchair could get lost or mis-directed.
If the plane has a closet that a folding wheelchair will fit into, they are required to allow at least one wheelchair to be carried in the closet (first come, first serve). A mobility device takes priority over whatever would normally go into that closet (like First Class passengers coats or hanging bags). The flight attendents will often fight you on that ("I need that closet for the First Class coats!"), but the gate agents have been our allies when we have asked to use the closet.
They used to automatically do preboarding for people with disabilities. We've found the last few years that they only do preboarding if you ask. On our last trip to Orlando, even though we had asked for preboarding, they "forgot". Since I have to partially take DD's wheelchair apart, I'm not shy about asking and did barge past the First Class passengers to board.
Don't be in a rush to get out because it takes a while to get the wheelchair delivered to the gate. The last few times we traveled, there were a lot of strollers and we couldn't get to DD's wheelchair until the plane was almost empty.
You could gate check the wheelchair and have it delivered to the baggage if you want (and DME would pick it up), but I'd probably just receive it at the gate and bring it on the DME transport. That way, you have it to use in the airport, you are sure it made it OK before you leave the airport and you have it to use at the resort right away.
Call DME and let them know you have a wheelchair. She would have a choice of loading the wheelchair in the riding portion of the bus (and ride in it or traqnsfer to a seat), or she could ask them to load it in the storage area where the carryons will be loaded. Discuss this when you call.
PS.
If you want more info, use the link in my signature to get to the disABILITIES Board.
PSS.
A wheelchair doesn't count against your baggage allowance.
