Wow, that was cool. I have spent several of weekends out at the sand dunes. In the winter we went about every weekend. Have seen some CRAZY stuff there for sure. During Thanksgiving it is vehicles for as far as the eyes can see. Memories.
I lived in Yuma for 5 years. The air ambulance helicopters were picking up somebody just about every weekend over there. I stayed away from the crazies on the dunes and did most of my 4 wheeling in the Kofa and Castle Dome mtns or along the border between Yuma and Organ Pipe (Camino Del Diablo).
I rode some dunes in SW Co years ago. We took 4 wheelers out there and had a blast. I've done the rockcrawler thing for the last few years with a guy I work with. I'll climb dunes anyday than drop 20 foot straight off a rock wall in a jeep on steroids.