I wore DD in an Ergo at the parks from the time she was 22 months to 4 years. (After that she was just too heavy, so now she just walks.) I loved the Ergo for ease in getting on my back by myself and comfort. I also like the little zipper pouch that's built in to keep a few small things in.
When she was 22 months we went to DL and I wore her on my front while she napped. I wore her on POC, Pinocchio, the storybook boat ride, and maybe a few other similar rides. The only ride that made me take her off was Jungle Cruise. I didn't understand why, but I just took her out and held her on my lap. Luckily, she stayed asleep, and I put her back in the carrier after the ride.