Okay, great, something I can answer!
I'm a solid 24, with big hips and butt. (SWEAR to me that this will not be used against me later!) There's no ride at DL or DCA that I wanted to ride that I couldn't ride. What everyone said is true, Orange Stinger has a weight limit which I exceed. However, I had no desire to ride it--not my kind of ride. Similairly, I don't ride roller coasters, so California Screamin' wasn't ventured, nor did I try Maliboomer.
I found the rides at DL and DCA much more agreeable to my size than the local amusement park. I wouldn't recommend the Rocket Rods, they made me uncomfortable, but you can certainly ride them if you desire. On Mulholland Madness, they preferred that I not ride with my children because my stomach prevented the bar from getting down as far as they wanted. However, they do have a bar adapter readily available--and by that, I mean right at the loading area--which they can slip on, which makes it safe for me to ride with my child. This wasn't a big deal--I have two children, who rode together, and I rode with my hubby. On most of the rides, I ride with one of my kids, and my hubby rides with the other. On rides where my hubby and I ride together, some can be uncomfortable, but doable--the ones like this that come to mind are Alice in Wonderland, The Many Adventures of Winnie the Pooh (no leg room!), and Big Thunder Mountain Railroad. My husband also felt claustrophobic, and he felt that it was the size of the ride rather than my weight. I didn't even try Dumbo, and it seems to me that a lot of adults wouldn't be comfortable on this ride.
Also, I wanted to add that at no point did any cast member make me feel uncomfortable for my size. You know how it can be--I was very comfortable at DL.