make reservations on reserveamerica.com and look for oceano dunes. Always good to make reservations before you go to make sure you can get in. And 4x2...just drive smart, air down, and you should do just fine. Just no hill climbing or anything stupid. With that said...
there is a group of about 10/12 trucks (4 long travel explorers) heading out the weekend before. Not to take anyone away from the origional dates, but if you you CANT make those, try the weekend before. It should be a good time.