Greetings, Leanna!
Welcome to the Disney Parks Moms Panel. I just love helping other families from the Land of Enchantment plan their trips to the Happiest Place on Earth.
Disneyland Resort is always very accommodating to Guests with special needs of all kinds from dietary or mobility needs to helping Guests who have
sensory or cognitive disabilities have a magical experience in the parks. It sounds like you will want to head to Guest Relations when you arrive to inquire about using your son's "stroller as a wheelchair." With this service you can leave your child in a stroller just as if it was a wheelchair which will give you some more flexibility in the parks. Guest Relations is located in City Hall of Town Square in Disneyland Park. You may also want to ask about the
Disability Access Service (DAS) to see if this is something that would benefit your family. This allows you to schedule a return time to certain attractions if waiting in a conventional queue is challenging.
If you don't have some already, I also suggest bringing a pair of noise cancelling ear muffs for your son if loud noises are a concern. As an infant all the way up to four years old, my son has had issues with loud noises such as fireworks. We always bring these ear muff/headphones to block some of the loud noises. They were also great if he ever fell asleep in his stroller to block loud noises and music.
I hope this helps, and please return if you have any other trip-planning questions!
-Jennifer