Diablo Dropoff is surrounded by a network of trails in Anza-Borrego Desert State Park. How hard this obstacle/trail is depends greatly upon weather conditions and seismic activity. The first time I went through Diablo Dropoff in 2012, the dropoff was heavily eroded and rutted.This gradually got worse until the dropoff was impassable due to part of the trail collapsing. Sometime later, the trail was restored and the dropoff was pretty mild. As always, the trail is gradually degrading and becoming more interesting to drive through. After going down the dropoff, there a few rocky washes and the trail gets easy again. A good, stock 4×4 with some ground clearance should be able to make it through the trail.
Even without the trail being difficult though, the views are spectacular and worth taking a look at even if you don’t drive all the way through. Since their is a lot of seismic activity in the area, don’t spend to much time in the mud caves or under overhangs. Rainstorms can also cause the cliffs to collapse. From the southern end, this trail can be reached by taking S-2, exiting onto Canyon Sin Nombre, heading north and turning right onto Arroyo Seco Del Diablo after about five miles, then turning right after seeing the sign for Diablo Dropoff after about six miles. There are other ways of reaching this trail, which I will happily type up about in due time or for anyone who asks. Here are the pictures, enjoy!
Edit: Below is some video footage on a trail run with some friends.
Second edit: Here’s some more footage with better lighting: