One of my readers suggested this site: Autistic Globetrotting: Autism Travel Made Easy.
I haven't gone through the whole thing as yet but thus far their tips are helpful.
It would be great if hotels had designated "autism" rooms like they have wheelchair-accessible rooms. Rooms which would be quiet and could have extra security or alarms on the doors.
We use a chain of jingle bells when we stay in a hotel. A little tape to secure it to the door and we have an instant alarm which will sound if one of the boys decides to go exploring at night. Alex can reach it but if he tries to remove it, it will still chime. It makes for a restless night of sleep but we manage.
My big concern is bed-wetting. I've tried bringing tarps to put under the sheets but the texture irritates him and he'll go through the sheet to get at it. I think I'll bring a proper fitted sheet with us to Disney, which means I'll have to verify the bed size.
As long as he doesn't soak the mattress, everything else is easily changed and dealt with.
We'll also plan to keep him up late and make him get up at the first signs of alertness, reducing the chance of an accident.
The Autistic Globetrotter's site made light of some of the concerns. They dismissed parents who find it overwhelming to travel as simply being unprepared. While I don't think travel is automatically off the table, it is certainly far more exhausting than travelling with a typical child. I can understand families who simply choose to avoid it.
But whatever their attitude, they are certainly full of advice and ideas to try.