You can use fast pass for the rides that the young one can go on as well, so that all of you can ride together, but for the rides with height requirements, get only ONE fast pass for each ride. An example: Get 1 fast pass using your ticket for splash, and 1 fast pass for thunder with your wifes ticket. when the first fast pass time is up, go to that ride, all 3 of you go to the fast pass entrance, tell the cast member you need to do child swap, they give you the child swap pass, the first parent rides going through the fast pass line, then the second parent goes through the fast pass line with the child swap pass. Then you can go to the 2nd ride and repeat, one parent using a fast pass, adn the second using a child swap. That way neither of you has to wait in a stand by line.