OP,
I've been lurking the forum for months, but decided to register just because I'm in the same boat with you and hopefully can help.
I've been taking my son camping/overlanding, boating, and all since he was about 2 and he was diagnosed about a year ago. My son is hyper verbal, so that's a difference, but he struggles with impulse control and other things typical kids do, but just a bit more so. Like yours, he loves the outdoors, is full of energy, and very fearless. He's a bit over 4 now and he begs to go on camping trips constantly. "Sleeping in the truck" is on his short list of favorite things to do.
In a lot of ways, getting to this point was a struggle. He has an irrational fear of bugs - his only fear to date, potty training is difficult for him (hopefully you're out of these woods!), getting him to settle down while sharing a space with me led to a few sleepless nights (he has been sleeping in his room since he was a baby). However, I adore the time we spend together and being in the woods is a time where he can be his autistic-and-otherwise self. It's a sanctuary for him now, like it is for me and it's awesome. Totally worth the hassle. Now to some tips.
Have realistic expectations for the first few trips: I knew I should have done this, but after he handled fishing and boating so well at 2, i thought he'd be ready for a trip to my hunting land to camp. After a 3 hour car ride with truck problems (turned 10 hours), hours of screaming about the dark just to turn a light on then scream about the bugs it attracted, after the struggle of setting up camp while my dad struggled to contain him, and after finally settling down just to realize at 3AM that he couldn't sleep sharing a tent with me and I couldn't sleep sweating all over him (summer was a rough choice) I realized what I should have done.
I should have eased him into it. Replicate whatever camping setup you're going to do on the trailp in your backyard, a lot. If it's too hard for either of you, bail to the house and try again the next night or whenever. Once that works, go to a camp site nearby and make it a night or two. Build to a goal and get there, together. Like anything else in regards to their autism, I find when it's on my schedule I stress us both out. When it's on his, we still have fun.
Once acclimated to sleeping and eating in those conditions, that's a big battle won. As far as safety, my kiddo listens better to me in the unknown and we just built on that. He takes safety in the woods seriously because I do, but I just played what I know about my boy, here. I did enforce holding hands until I showed him thorny bushes, loose rocks, and other hazards. Once he got that down, slowly I let him do it in his own. Now, he runs laps around me while we hike. This, unlike the actual camping, I did take slowly. Park trails while fishing accelerated him on this, we practiced him listening and walking safely and near me while I fished locally and it has translated to overlanding. Now, he can run off and gather kindling for fire starting around camp and I barely worry about him lol.
Then the last real thing that immediately comes to mind is to bring a sanctuary for him. For my kid, alone time, a form of confinement, and no bugs was very important to him. So, when I used to tent camp, I brought a tent that fit inside my tent and loaded it and a pack and play with toys to let him be free but safe and away from bugs - he was 2 at the time. Now that he's older, he gets some screen time in his carseat for a bit to calm his nerves. Or he sits in a camp chair with some toy trucks near me while I cook or whatever. But the things that bring your kid comfort at home, replicate them on the trail. I use this to help level set him often, and we always have a good time. I really mean that, the work is really in the past. I hate to admit this, but I used to long to camp or fish without him, to "relax" like I used to in the woods. But now, I can and do relax with him, and honestly don't want to go without him. But ya, that's about my best advice.
Except general kid advice: tons of favorite snacks, wipes, and stick/rock throwing.
I know this is all basic, but it worked for me and my boy. Hope it helps even a bit!
Also, despite the paragraphs of what I learned works for my kid, I really don't regret what I ultimately have always decided to do with my kid. Just go for it and learn along the way. I figured these things out, but ultimately, we still just went camping and in the woods a lot and he learned like any other kid but with a few other considerations that popped up along the way. Have fun!
