I have no ASD dx for my DS yet but he loves camping. We go to a place called www.fforestfields.co.uk
There's no club or playground or anything like that, but the kids just love it. When we went in August there was a little boy in the tent opposite who I presumed had ASD. It was lovely to see the freedom he had as the site is so safe. There is water around - a small pond, a boating lake which the site lend you kayaks to go on, and a fishing lake, but apart from the pond, they are all away from the main site.
I think you should give it a go silk. Give it a practice in the garden if you can so your DC can get used to the tent and then go for it!