What do you consider a "good" camping area? If you are in a self-contained trailer, almost anywhere will work for family camping. If you are tenting it, and dependent on installed toilet facilities, you are out of luck for "family" camping.
The lack of family-friendly camping is why I'm switching away from the BookCliffs as my GS spike hunting area. It's a great place for a lot of things, but not young family activities, or general camping if you want any accommodations.
That said, there are some slightly improved spots right along the ridge road, east of where Seep Ridge rd comes to the top. It is nice and shaded in the firs, with fire rings, benches and all. I'd be a little concerned about the lack of restroom facilities, and what others may have used while there. But it is a pretty place. It's nice and central, shaded, not too far from fresh water (PR springs), etc. PR springs is another place if you have a self-contained trailer, and good 4wd to get out if it rains at all.
Heck, if you want centrally located, have a self-contained trailer, why go any further than the level open spots just at the end of the pavement?
There is a lot of area to explore out there. If you are just going to drive, and do nothing more than drive, then perhaps centrally located would be ok. But, if it were me, getting to know the area again, I'd suggest breaking it up into three long weekends. Camp somewhere on McCook Ridge to the east one time to explore there, Rat Hole Ridge, etc. Then another centrally, to explore the central spine, Patterson, Black Horse, and over to Seep Ridge. Then the third to explore the area east of Seep ridge. Even just driving without stepping out to look around, you still might need three weekends+.