When Mac and Dee get stuck in the slide, you can seen him holding onto a handle.
When Frank and Charlie go down the racing slide together, a stunt double is used in place of Frank.
As Frank and Charlie go from ride to ride, they have a paper map that they use to check off the rides one by one as they complete them. However, the map never gets wet or crinkled. They probably just filmed them checking off the rides in one continuous segment and then edited the individual segments between each ride.