I've taken my cats camping, but it was in a tent. It was pretty crazy, I was between places and just decided to camp for a few days, so the cats (all 5) came along. I had large metal crates for them, 2 to a crate, and they liked riding in those. They could see out but weren't a problem for me driving. I have a large SUV. I set the crates outside with large towels over the tops for shade and they watched me set up the tent, they were fascinated by the whole thing, especially watching the ravens in the sky above us and looking out at the rocks.
After I got the large tent set up, I put them all in it. It was big enough for a litter box way over there, not close to me at all. They seemed pretty stoked, and since the tent had a floor I didn't worry they could get out. Keep in mind I was way out in the middle of nowhere near Canyonlands National park. Nary a soul for miles and miles, as it wasn't tourist season yet. No way was I going to lose a cat out there, so I was extremely careful.
During the night they all crawled in bed with me, so it must've got chilly, even though they each had little down blankets of their own. At dawn one started scratching at the tent side to see if she could
escape, but no way.
It wasn't something I'd really want to do again, but if my cats can tent camp, I think a trailer would be simple. I would personally microchip them so if they're lost someone might be able to ID them, plus collars and tags. I have one that's kind of precocious and she and I went for a short hike, she was on a leash, she loved it. The others hated the leash. They can also get out of about anything collar wise, as I'd experimented with them before going out. Test any collar at home first.
We survived. I've also taken the crew on trips to places like Montana, but that wasn't camping, we had a house destination. They meow a lot at first and then settle down.
And did I mention I also had four dogs with me?
Call me nuts...I'll agree. But it was an adventure.