Child Swapping Pass
DLR and WDW have the "child swap" that goes by various names. The party must wait in line as they normally would while using the GAC/disabled line, standby line or fastpass line. When they are done riding then the babysitter takes on or sometimes two people with them through fastpass. Number rarely is three but sometimes on something that seats 3 across they will allow a third person. The CM giving out the pass will tell you where to use the swapping pass.
Here is a list of rides at WDW that allow the use of the swapping pass.
http://www.wdwinfo.com/childswap.htm
http://mousepad.mouseplanet.com/archive/index.php/t-54933.html
That has a good explanation for those of you who get confused by Churchy a lot.
Single Rider Lines
This is offered at Test Track, Mission:SPACE and Expedition Everest. It is a fast way to ride with out the fastpass if you do not mind being separated from your party. Mission: SPACE seats four persons so when there is an empty seat they take a single rider. The other two rides sit two people per row and too often there is an empty seat.
GAC
The GAC is for persons with invisible handicaps that is a tool used by CMs to discreetly and quickly determine the special needs of guests. It is not meant to speed up things and too often can be slower. I would suggest you go to guest relations and explain your situation and they will tell you if a GAC if for you.
Practice
Practice waiting in line with him and reward him for waiting 15 minutes in line for example. Some moms use bits of gummy bears, low carb snacks, and other treats to encourage good behavior. Fidget toys, beads, hand held toys, and audio/visual stuff can make the wait not so bad. Happiness in lines make the child not hate lines so much and maybe even like lines. Some parents use ipods, walkman radios, gameboys, and other audiovisual busy work.
Some kids love having the trip in written or pictures showing everything that will happen. Use videos from
youtube and see what he likes to do. Talk with him about what he likes. One boy detested a ride because it was for girls, hrmph boys will be boys.
Planning
Planning the trip will make it possible to avoid most long lines. There are the child swapping pass, early magic hours, arriving early and storming the park, fastpasss, single rider lines, and timing the vacation to not be in the summer. Know where everything is and when you get to the parks have plans B-z ready in case you hit a speed bump. Long line at Dumbo so go ride the tea cups or Peter Pan. Plan on splitting the party and have mom and son then daddy and son then family times. The other two kids need to have fun as do you and dad.
Ask and you may receive. Some CMs will go out of their way to make life easier for guests. Sometimes it works and sometimes it does not work.
Good luck on your trip
hugs and merry christmas from laurie