I don't know about nowadays, but 7-8 years ago when when we traveled there in our Class C motorhome RV'ers didn't need to stay in campgrounds in Death Valley.
We learned what the off-road camping rules were and then dry camped out in the middle of nowhere a short ways off a 4X4 road in Death Valley. We didn't need 4X4 capability or high clearance where we were camping, though. Three of us couples in three Class C motorhomes had a great time camping out among the rocks under brilliant night skies. A great experience all around.