Disney is very size friendly. Some rides are more comfortable than others, depending on where you carry the weight. For example, if you carry more of the weight in your hips then the Astro Orbiter can be a snug fit getting in and out, but if you carry your weight in your stomach area, it's not as much of a concern. Some of the theater show seats can be a little snug also if you're heavier in the hips. If you carry weight in your stomach, watch out for lap bars if you are sharing a seat with your child - BTMRR for example. If the lap bar stops on you, but doesn't go down far enough to secure your daughter, you will want to be aware.
We have several larger people in our friends and family circle, and so far, there haven't been any issues with someone not fitting on a ride at all. Universal, however, is a totally different story . . . . .