We stayed at Winderbandi - nice spot, although access out with a boat is a real pain in the backside when its anywhere near low tide - very, very close to the surface coral.
I would ring Phil, or email him - my understanding is the bore is only accessible if you know someone in that camp ground that will let you in. I was told people just use a bilge pump - I can't see why you couldn't pump it straight into the van, with the right filters perhaps.
We found Phil extremely helpful and easy going - he should be able to sort ya out
thanks Aaron, we contacted the station and are booked in, aparently the water is 2 to 3 meters down, we bought a bilge pump in Karratha and set it up to attach to the caravan water hose that goes thru a b.e.s.t. filter