I have not, but I have been out there in a 4x4 and I wouldn't do it. It looks like lots of fun, but I'm not taking my motorhome out there.
My understanding is you can pay a tow company in advance to help you get in and help you get out. I don't remember the exact numbers, but if you pay in advance it was something like $150 to both get you in and get you out. But if you don't pay to have them help you in and out and you get stuck then they charge you $400 or $500 to pull you out. And the times I've been out there I have seen a lot of motorhomes and trucks and everything else stuck in that sand. I even got my Jeep Wrangler 4x4 stuck in the sand, but it was pretty easy to get out. You bury the back axle of a motorhome in the sand and my understand is you have little choice other than the tow company to get you out. I have heard stories of people bringing some heavy duty timbers with them and using them in combinations with your jacks to get unstuck, but it would have to be some pretty heavy lumber.
