I am stressing on finding a spot. I am heading out Thursday Night.
Camping is definitely full at the State Park. The RV park across the road may have some tent sites but it kind of sucks. You get just enough space to pitch your tent in a small field with a bunch of other tents. There is BLM land off of 18rd that has good primative camping. That will probably fill up Thursday sometime as it is first come first serve. It is also a long haul to the festivites in town (25 minutes????)
If you do camp out at 18rd Leave No Trace ethics are very important. It is a pretty fragile desert ecosystem that seems to come under scrutiny by the BLM quite a bit. There are several pit toilets in the area but no services at all. Best bet at this point is try the RV park for one of their cabins or get a Hotel.