I'm a super-sized BBW (5'4"-520 lbs.) and am planning my final trip to WDW for Easter before I have gastric bypass. To answer your question, I have been going to WDW for several years at my present size and the only rides I have a problem with (meaning I cannot ride them) are the lap belts on TEST TRACK, MISSION: SPACE (obviously), and STAR TOURS. The seats on DINOSAUR are snug but everything else has been fine. I have not ridden ROCK-N-ROLLER COASTER but I'm told that the front car could accomodate me without issue. EXPEDITION EVEREST looks to have the same kind of seat as MUMMY at Universal (with a personal lap bar that your thighs must squeeze through in order for it to lock) so I wouldn't even attempt that. In most instances when a seat belt is involved, an extender is available. Not being able to experience these few attractions has not stopped me from having the time of my life each time I visit WDW. There is sooooo much that I can ride and do and see that it doesn't bother me. Hope this helps!!! :wave: