Well the canyon sin nombre/drop off/fishcreek/split mountain is nice. Then maybe the Salton Sea Test Base if there is time.
Or there is the slot canyon tour with a little hiking. Slots near the SVRA (With a TINY bit of Maob back there!) Then over to the palms, pumpkin patch, and the truck haven trail. Then either the slots there or maybe take the Jeep Safari Trail.
There is a MAJOR drop off near the first slots. Honestly it scares me a little

I usually go around the back side and avoid it. It's difficulty varies from year to year though. The "Drop Off" into fish creek used to be a lot harder 20 years ago. It's completely graded down now...