We love Disney and before my son was dx with SPD, we could not figure out why he was so awful there! He is usually pretty easy going but he just fell apart at Disney. I remember my dad who is usually so good with the kids just losing it with him, shouting at him as my little guy was having a MASSIVE MELTDOWN!!!!!!!!!!!!!
We were all so irritated with him for being so demanding, so obnoxious, so tantrumy...he even got lost one evening which was really scary.
Now that I know about SPD, I feel so bad that everyone was so mad at him! We haven't been back since but he has handled other parks well so I think I have figured out how to help him and maybe we will try again soon.
Sorry you had a tough time, glad they enjoyed Legos.
My son loved the big sprinkler/fountain at Downtown Disney and spent one afternoon running through them - I think that was his favorite part!