We talked a while back, about how there was very little that piglet sized kiddos can ride. In fact, they can ride almost everything! But what about the larger set? The pooh sized riders? The folks that are a little heavier? I've got good news for you as well! There is very little (if anything!) that you can't ride, too!!
Walt Disney World was created so that EVERYONE could enjoy the rides! At Walt Disney World, you will find many different styles of seats. Here's what you may run across.
You've got your bench style, like on It's A Small World, and Pirates of the Caribbean. those are the style seats that allow you to have enough room comfortable, without being put into a "seat"
A lap bar style seat is typically on a bench style seat, like Peter Pan's Flight, or The Many Adventures of Winnie the Pooh, where a safety bar is pulled up towards you. This won't be a problem if riding with a companion of the same size, or alone, but use caution if a Piglet sized rider is with you, so that they don't slip out from under that restraint, say, when flying over Neverland.
Over the Shoulders
An over the shoulder restraint would be in a ride like Primeval Whirl. A restraint bar comes down over your shoulders, and locks, keeping you from falling on a ride that might be jerkier, or spinny.
On some rides, like Star Tours, you'll have a lap bet as your restraint. While you shouldn't have a problem, belt extenders are offered, so that everyone can enjoy the ride. The seats are usually wide enough, that we've never seen a rider leave, disappointed.
In some attractions, you'll be seated in movie theater style seats. These are usual size, so if you don't have a problem back home, it's unlikely you'll have a problem here.
Now this is the trickiest style seating. A very few rides have a slightly molded seat, that while you can still fit in, might not feel too comfortable on the tush. Seven Dwarves Mine Train is one. Still doable, and luckily the ride isn't too long, but just might not be the comfiest.
As you can see, there really isn't much at all you won't be able to do. Walt Disney World can easily accommodate you, so no matter your age, or size, go enough yourself! With so much to see and do, you're going to have an amazing trip!