OK -- Here is what I have heard you can do (but of course I have never and would never do this

).
Get two fastpasses for RnRC for example. Go to fastpass line when the time window is correct, present ONE fastpass and ask for a Kid switchpass. They will give you a switchpass good for up to two people anytime that day. One parent goes on the ride. When he comes out, go up and use the switchpass for second parent Then, do it all again if you want with the second fastpass and you'll get in 4 rides in a very short period of time!.