Unlike some of New Mexico’s better known canyons, like the one at Kasha-Katuwe Tent Rocks National Monument, Diablo Canyon is relatively unknown. At Tent Rocks, you must usually share the trail with a bunch of other people. That’s not the case with Diablo Canyon.
That’s probably partly because the drive to this recreation area is a “hold on to your fillings,” experience. However, assuming the weather’s decent, you can make it here in a regular car. The trip is definitely easier in a 4WD vehicle if that's an option.
The BLM operates the Diablo Canyon Recreation Area. There are no admission or parking fees to use this land. However, neither are there any amenities. Bring anything you might need, including plenty of water.