Years before my DD was born I took a class in college. I don't remember most of the stuff taught in the class, but, I do remember this: Prepare More, Punish Less.
My DD loves to have her schedule written out and everything discussed to have it settled in her mind. While we are talking about her schedule, I also go through and discuss the appropriate behavior. Reading the cues is important. I can usually tell my DD is getting overwhelmed, frustrated or anxious. My DD is highly verbal. In fact, she is diagnosed with a Non-Verbal Learning Disability which is opposite of it's title. We discuss everything. I can tell when things are getting too much for her because she will begin to shut down.
You and I are in the same situation where it is just to 2 of us. In a lot of ways, things are easier. But in some other ways, it is harder. Teaching to share, take turns, you don't always get you way, etc. are hard for children with ASD and even more so when it is just to 2 of you.
Just a couple of books to help you through this experience:
Life Animated by Ron Suskind is probably the best book I've ever read. Just to point out that your son is "just like everyone else - only more so and less so." Also, your son is "different but not diminished."
The Explosive Child by Ross Greene. I am not saying your child is explosive but it helps put things into perspective. I wish I had this book years ago when my DD was struggling.
It's So Difficult To Be Your Friend by Rick Lavoie. I love everything I've read from Rick Lavoie. Very pragmatic and offers great insight and suggestions on how to help your child manage their world - not only socially but in every day.
I am sorry this isn't much help with your upcoming trip.