Hi, DeAnna! Over the past few decades, I have traveled with my mother (who has multiple and an increasing number of disabilities) to Walt Disney World. It is amazing to see the progress that the resort has made to accommodate those with various limitations, and it sure has made our world as her caregivers easier, too. Most Disney resort buses are equipped with lifts and/or ramps for wheelchairs and Electric Convenience Vehicles (ECVs). My mom has been wheeled onto buses and strapped in for the ride, and she has elected to transfer to a regular seat and have her wheelchair secured without her in it. Most of the time and under normal circumstances, bus drivers will defer to the guests' wishes and needs.
Of course, as you are keenly aware, sometimes it just takes a little more patience when traveling with someone with disabilities. We've had extra waits for buses with wheelchair availability. Also, we've been refused travel on some water taxi's because the water levels were off, and it wouldn't have been safe to transport her onto the boat. Now, since my mom has several issues, it is best for us to use a car with her parking placard rather than have her endure waits for transportation. I hope our experiences and situation have given you some idea of what to expect as well as help you plan.
Please let me know if there's anything else I can do to alleviate any other concerns you may have and make planning your trip almost as much fun as taking it! Have a wonderful day and a magical vacation!