Thanks Paul! I'll go with Tamarisk unless you have any other suggestions for nearby camping? It doesn't have to be that close to where we hit the trail last week. We are meeting FrankB at 10:15am at Fish Creek / Sandstone Cyn.
Mike, there is also a primitive camp (but with vault toilets) at Fish Creek, about 1.4 miles in from the end of Split Mountain Road, on the left up on the mesa. No big shade trees like at Tamarisk though, but also free, just first come first serve as to spaces. I think there are fire pits.
Alternately, you can camp anywhere in the State Park, just pull off the road (but not creating a new trail), and be sure to have a metal container for your fire (no ground fires allowed, they will cite you). There are also toilets and showers with running water at the ranger station in Ocotillo Wells, on the left about a mile west of Split Mountain Road as you are heading east.