Get the GAC at the first park you visit. Don't try to see if you can manage without it.
Don't press them to go on rides they are not ready for.
Ask for a quiet room location at your hotel. Time shares with a kitchen/washer/dryer can be very comfortable to unwind and wash favorite clothes.
Don't leave any favorite sleep items (blankie, etc) in the bed while out of the room. The maid may take it with the sheets (Can be retrieved by calling housekeeping!
)
Use a stroller past the usual stroller age.
Go during low attendance times.
Bring a drink and small snacks to carry around with you.
Two sets of earplugs for when he drops the first somewhere
Make ADRs for restaurants - less wait
Look at the menus in advance an allears to see if they offer what your child will eat - also check the lunch menu if there is something that he will eat and you are there at dinner they may make it for you.
Specify to the waiter if you need your food a special way e.g., plain or on separate plates
Take a break every afternoon. Don't try to do too much.
Glow necklaces/bracelets help you keep an eye on your child in the dark.
Bring an MD note for the plane to assure that you are seated together.
The portable DVD can be a big help for car trips or plane trips.
Breakfast in the room (in front of the tv) can be very relaxing for an AS kid
The
LEGO store in Downtown Disney is my son's go to place
My son likes to do the same rides each time we are at the park (loves repetition)
Pin trading/collecting can be a good way to build social skills.
Plan ahead. Don't play it by ear, but do be flexible (you know he won't be!!
)