Hey
@Oldvolks I can help with this!
So each campsite in Chisos Basin only allows really two vehicles. 1-car & 1-trailer. The campsite hosts luckily allowed us to keep both our trailers at one site with one vehicle. I had to park my Jeep ~100-yds or so up in the overflow parking lot.
Here's a picture of that set-up.
I'd recommend getting multiple side-by-side spots.
From my experience, I'd suggest getting the sites noted by the green stars below first, then maybe the orange stars next. This way you can technically have 3 sites but can all group up in the middle for hanging out.
Note though that you're parking on asphalt, not dirt and not "within" the individual campsite.
There is some dispersed camping in the park though that I haven't done yet.
Also, no real wood fires are allowed in the park, must be propane.
In October, the weather could be decent along the river. Cottonwood (was 100-deg at night in May 2022) campground was quite open and may be better suited for group camping.
However, Chisos Basin is by far the best campground of the three in the park. Best views, coolest temps, best facilities, etc. It's just not super good for groups of trailers.