I'll ramble since I've wandered out to 6 camping spots in Baja & have read up on some others (farther away). It's getting cold, so Sea of Cortez will be calling again at some point.
El Salto (West edge of Valle de Guadalupe).
Pay at the gate, big campground with a lot of nooks to choose from, great short hike in the a.m. to a waterfall/scenic spot. Only about ~15 minute drive from Cocina de Dona Esthela for breakfast too. For short getaway or to do Valle while camping, this would be an easy spot from Rosarito/TJ.
San Antonio de Necua (Valle de Guadalupe - about 2 miles East of L.A. Cetto).
You literally drive through a (one-track
) sandy river bed, up into a Kumiai town (replete with native lanugage & spanish on the signs). If they're there at the gate, pay the lady and you have the whole campground to yourself. Bunch of farm animals nearby, far enough away for that super-clear sky, felt safe and there is some $$ in that town (for Mexico).
Constitucion 1857 - National Park.
Was about 3 hours from TJ, including ~20 miles on dirt roads upon leaving Ojos Negros (dairy region where they're going to build a new Ensenada Airport). Camped @ the famous Laguna Hanson, only downside was the free-grazing cattle literally came w/in 10 feet of our tent (while we were hiding in the car), should probably set up barriers next time, lol. Nice to get the scent/look of pine trees while still in Baja.
Erendira
~90 minutes South of Ensenada, there's an iconic cluster of rocks that we wanted to camp at, but with only 2 people it seemed smarter to camp in front of the hostel on the hill, lol.
Rocks/beach below with a huge group of people/somehwere else on the beach would be legit in that area, but you're unprotected there and Baja forums said be aware in those parts (generally speaking).
San Felipe
Camped under a palapa @ Pete's Camp, had it all to ourselves the week before X-mas. Probably better spots here, but got the job done. It was really cool to see the tide ~1 mile out before sunset, then wake up with the Sea 20 meters from out tent (one of the largest tidal bores in the World from the flow of the Colorado River Delta south of Mexicali).
Bahia de Los Angeles/Campo Archelon
7 hours South of Mexicali, REALLY legit spot with the old volcanic/geologic formations making a sweet cove. Would be great to chill/fish with a kayak for a couple of days. The Valley of the Giants/huge cacti and wildflower blooms (in March after long winter rains) on the drive in were also stunning. Drive for hours through zero-population to get there, reminds you of how vast Baja is.
Had a 22 mile rough-dirt road detour in a Honda, was definitely glad to be packing a full spare in case.
Still on the list
San Pedro de Mortir - Highest point (?) in Baja with an observatory @ 10,000 feet, supposedly you can see both the Sea of Cortez @ Pacific Ocean on a Clear Day. They get a decent amount of snow up there too in the winter.
Canon de Guadalupe - drive through Laguna Salada (dry lakebed below sea level, the San Andreas fault runs through/near there), hot springs and old native rock paintings (like there are up-and-down much of Baja). Think they even have a bus that runs to/from San Diego for big groups.
La Poma/Km 133.5. Made a note in cell phone while driving by, looks like a pretty legit volcanic cove a ways South of Puertocitos (and still 1-day getaway driving distance from TJ/Rosarito).
Mission San Borja
There's a lot of ruins of the Missions that were built in Baja in the 1700s & 1800s (the last one being in Valle de Guadalupe). There's one that's restored near Bahia de Los Angeles that lets you camp. If you have a good 4x4 or rent a driver from Bahia de Los Angeles to get there...
Mission Santa Maria & Oasis/Hot Springs
Speaking of 4X4's, this one you have to go ~15 miles off-road and the last mile is supposed to be tough - the reward is your own personal oasis/hot springs in the middle of nowhere (so a large group is also probably advised, lol).
The people on the Baja Nomad forums generally say the closer you camp to the road, the more dangerous it is. The farther away, the better (if you're gangster-camping - Baja is wide, wide open once you travel South - could do that for months/til your supplies run out if you want).
/fin ramble.