Hey Howdy Hey Michele and welcome to planDisney!
With getting around Walt Disney World Resort, the attraction vehicles and lines were built for guests of all abilities and accommodations are available to help make your trip Magical! Any trip to Walt Disney World should not be taken lightly, as there is a lot to do to prepare for the trip, so I am happy to answer your question on expectations.
I feel the biggest thing to get ready for is the heat. Things are warming up here in the Midwest, but they do not compare to the Florida sun. As much as you can, get out on the warm days and try and get used to the warmer weather. Make sure to try and bring things like cooling towels, fans and water bottles to help manage the warmer weather. Did you know that you can fill up your water bottle at most counter-service locations free of charge!
Although many of the attraction lines can handle strollers and wheelchairs, some may not be able to. If standing and walking are things that your son has difficulty with, I would look into
Disney's Disability Access Service. If you apply and qualify for this service, your party will have the ability to make specific reservations for attractions ahead of time and experience reduced wait times. You will either check-in with a Cast Member at the entrance of the attraction or make reservations on your My Disney Experience app for these selections. It is super convenient for Guests with difficulty standing and walking in long lines.
For some reason, if the Disability Access Services does not work, I would recommend looking into
Disney Genie+. This is another tool to help decrease wait times in lines and ensure that you see most if not all of your "must-do" attractions. This can be purchased ahead of time or on the day of your park ticket through your My Disney Experience app.
The other things I would recommend have to do with taking breaks. Make sure that you have plenty of options throughout the park for some downtime. No matter if it is getting on an attraction indoors, like
Muppet*Vision 3D, where you spend some time watching a show in airconditioning or enjoying a meal at
50's Prime Time Cafe for a sit-down meal. You might need some time to get off of your feet, enjoy some time in the airconditioning as well as a refreshing snack like the popular
Peanut Butter & Jelly Milk Shake at 50's Prime Time Cafe. Reservations are highly encouraged but you can always stop by and request seating at the Tune-in Lounge which accommodates limited numbers of guests on a first come first serve basis.
Another tip to help plan ahead is by preparing for any concerns with transfers.
Disney has some great information on what to expect with most attractions in the parks if you are concerned about transferring to the ride vehicles and navigating the distances with assistive devices.
The final tip I have for you is if your son works with a physical therapist in school or attends physical therapy outside of school I would talk to them about your concerns. Therapists are specialized in knowing the specifics of your son's case with regards to strength and endurance and should be able to give you specialized tips on navigating the parks as well as any concerns you may have with regards to transfers.
Have a Magical trip,
Nick