When we were there in 2008 we camped in the Kalpowar Crossing, there were only a few sites suitable for Caravan/Camper. The board at the front was marked with people in them but when we got in there all the sites were jumbled.
IF you get a site that can handle a van/camper your ok, if not youll have bollards in your way.
We stayed in site 9 IIRC. It worked for us but wasnt ideal. Sites 7 & 8 were ok