These campsites are located in what is called Bride's Canyon, off of the Gemini Bridges Road. Also note that it is currently listed on Google Maps as Poison Spider Trail. Not sure why. 

The Pros: 

This location is stunningly beautiful. The campsites are spacious (so you could fit several vehicles in each. And the campsites are relatively secluded so you aren't right on top of  your neighbors. You have copious amounts of shade in the canyon from the red rock canyon walls on each side (depending on time of day) while still having clear night sky viewing. 

The Cons: 

This is NOT an easy place to access. 

Option 1: drive in 9.3mi of dirt road, the last 5.3 of which is pretty rough

Option 2: you drive in 4.3mi of pretty rough road from the hiqhway along a dugway on the side of a cliff. 

Note: we made it in via option 2 and out via option 1 with our lower-clearance pickup truck. I'm an experienced off-road driver. However, we pulled in our off-road overland squaredrop trailer. While the road is such that even a pickup with lousy clearance can do it if you take your time, I DO NOT advise trying to pull a trailer, even one with good clearance into this area. There are lots of tight corners, dips that bottom out your trailer hitch, and uneven areas that could cause your trailer to roll. We blew out a tire going around a particularly rocky curve about 1 mile in from the highway and spent the night stranded on the side of the road dug into the cliff. We also had the trailer slip sideways in a sandy curve where we ended up wedged against a post. Fortunately a guy with a decked out jeep and a winch came along and help extricate us. 

Bottom line, I would DEFINITELY camp here again, but I would DEFINITELY NOT take my trailer in.