Hi Karrie,
Disney is extremely sensitive and accommodating to guests with special needs.
There are wheelchair accessible rooms at all the WDW resort hotels. These have bathrooms with extra wide doors and roll in showers. Many of the hotels have zero entry pools and all have ramps throughout.
All of Disney's resort transport buses are wheelchair accessible, as is the monorail system.
In the parks, there are numerous wheelchair accessible restrooms in all locations. Many of the rides are accessible by rolling your wheelchair right on board, while at others guests will have to transfer out of the wheelchair in order to ride. The Walt Disney World website goes into detail about which rides are available in which manner for guests with
mobility issues. When you get to the parks, stop by the guest relations office. They will be able to provide you with maps indicating where the wheelchair entrances are to the attractions. You may also qualify for a Guest Assistance card which may allow you to wait in less crowded areas or be given other considerations.
A great resource for you would be a book called "Passporter's Open Mouse for Walt Disney World." This is available from Amazon.com. And gives step by step planning info for anyone with a medical challenge planning a trip to Walt Disney World.
We're happy to help you plan a magical visit with your very special little princess. Please ask us as many questions as you like and we'll do our best to get you the information you need.