Hello Abigail, and welcome to planDisney!
I fully understand the planning it takes to ensure that you and your family have what you need when you visit
Walt Disney World Resort, and a stroller is no exception.
Unfortunately, stroller wagons of any kind are not permitted at theme parks, regardless of their size and dimensions. You could visit Guest Services when you arrive at the theme parks and explain your circumstances, but I recommend being prepared to pivot and have an alternative option handy, as there are no guarantees. I know that this news isn’t very reassuring. Still, the good news is that you can
rent a stroller directly from the theme parks and Disney Springs, or you can contact a private mobility rental company like Scooterbug and rent a stroller from there. With the rental from Scooterbug, you can use that stroller when you are outside the theme parks, and they will deliver and pick it up from your resort. I hope this helps.
Please let us know if you have additional questions.
Have a magical day!
Raquel