If you get a permit from the Cabeza Prieta refuge folks in Ajo, it can be done via mail or fax, I didn't have to watch a video. If you go thru BLM or other entity ( Air Force folks) you have to take time out to do that. Depending on where you want to go it is mandatory to have 4wd for the El Camino. You only really need it at the Pinta sands area. They just don't want to be responsible for pulling you out of any sand traps.
I don't know about Charlie Bell area but I have driven the entire Camino 3 times, and gone in at Christmas Pass a couple of times. John Anninero's Adventuring in Arizona ( I think that's the title) details a summer backpack of the El Camino, and has a few road notes. Any backcountry touring book usually has some info on the Camino.
I've hiked in the Aqua Dulce, Growler mountains, Cabeza Prieta Peak, a couple of peaks out of Tule well, Tule tanks, some mines near the border, and of course Tinaja Altas. You will see some border patrol. There will be probably some evidence of some border crossers, but I have solo hiked and camped in that area and with prudence, never had a problem. Also some nice hiking at the Pinacate Lava Flow.
Really a lot to see and do on this historic route.
Have fun--I'll prolly be back out there Jan/Feb time frame.