We've camped at Organ Pipe with our 35' plus toad. Like John mentioned even 40' can fit. We LOVE that campground, no hook ups; but we still love it and I'm not a fan of no hook ups. It has great hiking, beautiful scenery and if you happen to be there after a good rain, the wild flowers are everywhere! The Sonoran desert is much different than other deserts, in that there is a lot more greenery and palo verde trees.
Marsha~