This is a great campground. Beautiful views, plenty of space and access to some great hiking.
The hike to Zapata Falls was very crowded, even when the campground wasn't full; a lot of people make the drive just for the falls. I would highly recommend the hike to Zapata Lake. It's strenuous but beautiful.
The road to the campground is very rough. Be prepared to go slow, especially if you have a small car. I have a small car and driving this road was one of the most stressful things I've ever done. Take your time. And let people who are going faster than you pass.
There are lots of places to camp here. I spent one night along Palm Canyon Road, where there were plenty of pull outs. There's also many spots up by Crystal Hill. Both places were easily accessible with a small car, just drive slow and be extra careful at rougher spots. There are signs that say "no camping beyond this point", but they are only referring to the land before you get the refuge. Once you enter the refuge you can camp just about anywhere. This is a very beautiful place, would highly recommend spending a night if you're in the area.
Convenient spot close to Organ Pipe Cactus National Monument. I got a little confused trying to find this spot at night, but once you find where the dirt road passes through the gate there are plenty of places to camp right there. There was only one other group there in October, but I would assume it gets more crowded during the winter months. It's a little close to the highway, so you will hear some cars passing by, but it's not too bad.