Hiya Chloe!
Welcome to planDisney!
I'm sorry to hear about your worsening mobility issues but I am glad you have come here to help plan your trip to Walt Disney World Resort. An
ECV (electric conveyance vehicle) or power chair is a great tool to make your trip much more comfortable. Walt
Disney World Resort has various ways they accommodate guests who use mobility devices. Some attractions such as Buzz Lightyear's Space Ranger Spin and Jungle Cruise
allow guests to remain in their wheelchair or ECV to experience the attraction. There are special ride vehicles that let guests roll right on and are then secured. You won't have to worry about leaving your power chair with anyone.
Other attractions have a Transfer Access Vehicle where you will have to leave your ECV behind but be provided a special seat or accommodation to make loading and unloading easier. There will be a space where Cast Members will store your vehicle. If the ride ends in a place different from where it starts they will make sure your ECV is waiting for you or assist you in getting to it. I suggest that whatever vehicle you bring, make sure to clearly label it with your name.
Finally,
other attractions require guests to transfer to a provided wheelchair and then to the ride vehicle. This includes Avatar Flight of Passage and Kali River Rapids. All transfers will have the assistance of a Cast Member but you will have to be able to move or have someone in your party help you. Your power chair will be stored in a designated place.
I suggest for each attraction ask the Cast Members if it will be moved and where it will be located when you exit the attraction. Each attraction has slightly different rules based on its layout and capacity. I have seen some attractions with so many ECV vehicles stored for guests that they had to move them to another nearby space.
I hope this was helpful and that you enjoy every moment of your upcoming trip!
Happy Planning!
-Nimmy