Off roading that I do. I have done quad racing Desert style, anything from Grand Prix to point to point racing. I'm adding a link for the local off road community here in Mexicali CODE. It's next race is Feb 11. I have a few friends racing this race in trucks or buggies, I will help run a pit for one vehicle.
http://www.codeoffroad.com.mx
What is close for off roading here in Mexicali is Laguna Salada it is typical Desert Racing, sand, rocks woops big and small and a dry lake bed that isn't so dry. Camping is the tough part, pretty much a tent, unless yountravelmback towards town to some small hotels, where out of town racers stay. If you have an RV that works but no electrical or water hook ups.
There is also a hot springs in this area with some camping never camped there but I could do the research. I have used the hot springs after a race which was relaxing.
About 45 minutes from Mexicali up the mountain 4000 ft level is more riding, I'm not very familiar with it though.
Then to the south is San Felipe home of the Baja 250 from SCORE racing, this is on gulf and lots of off road riding here, and you will find An American Community that you can rent homes or other places to bring RV's ( I believe)
If there are some seriousmpeoplemabout this I'm happy to do the leg work to get more info.
I know many worry about safety but I have been to all these places and livedmhere in Mexicali for the last 10 yrs. imam more secure living here thane when I was in San Diego or Orange County.