Hi, Shaun! This is a really great question, so I am so glad you stopped by with it. One of my fellow panelists recently measured the seat of the
Disney Double Strollers, as we do see similar questions often. The seat in that type stroller measures 19 inches across and 24 inches deep. However, there are some other things to consider when having an older child ride in it.
A few years ago, my then eight-year-old daughter injured her leg shortly before our trip to Walt Disney World Resort. I thought she would be fine walking around the theme parks, but her leg ended up hurting her too much. I considered one of these double strollers, as the seat dimensions were fine, but she proved to be too tall. There is a canopy overhang attached to the stroller and it does not collapse back like other at-home strollers. This does mean that it is recommended for use by children less than 45" tall. Also, there is a 100 pound weight limit. When recently trying to push two children in a stroller, I discovered why there is that limit. The strollers are really hard to turn when you meet that weight limit. In my experience, it did not make it unsteady, but I had a really hard time navigating it.
Shaun, there are
wheelchairs available that you may be able to rent at each theme park, subject to availability. Also, there are several stroller rental companies in the Orlando area from whom you could rent a larger stroller that may fit your child. Simply follow the Stroller Rental link I included above and look for the Disney Featured Providers. Hopefully one of these solutions will help you and your child find all the magic at Walt Disney World Resort!
Brandy