I have never been to Legoland or Sea World (though have been to Disney several times). Could you tell me if there are any weight restrictions or concerns at Legoland and SeaWorld?
I haven't been to Legoland, but I'll speak to Sea World. The only problems an overweight person might have at Sea World is the rides. There are three rides - Wild Arctic, Shipwreck Rapids, and Journey to Atlantis. Wild Artic is a motion simulator, much like Star Tours (but not as rough), Shipwreck Rapids is a water ride, much like Grizzly River Run, and Journey to Atlantis is a roller coaster. My only suggestion is to go to the parks and see it and decide if you'd be comfortable. There is also a gondola that you can pay to ride which might provide a challenge depending on one's size.
I don't know exact weight restrictions for Legoland, but the rides are small. I go with my son often and sometimes its hard for me to get it. My dad 5'6 220 lbs. - it's almost impossible to get in and out. Legoland is made for kids and the ride vehicles for the most part reflect that. Take a look at the website, it has a lot of pictures.