http://www.willangibushescapes.com/
Went here over the June long weekend this year.
8 bush camps spread over a large area (could very faintly here the generator on the camper at the next nearest site).
The tracks are mostly rocky/slate - so you certainly want to let your tyres down. They do warn you about slate at the sides of the track, so avoid cutting corners.
We had a group of: 2 Patrol GU, Patrol GQ, Jeep Cherokee, Toyota Prado .... All coped ok, although the jeep & Prado got a few light knocks underneath. All but 2 vehicles had A/T tyres and were fine.
They provide firewood regularly (during fire season) and the long-drops are very well maintained. Staff are lovely and very helpful, and they add new tracks on a regular basis.
It was our first trip in our 2006 GU Patrol, and I would certainly go back. You could prob do all of the tracks in 3 days (while still allowing plenty of fire/food/beer time ).
Also pretty cheap at $20 per couple per night, plus $45 per vehicle for tracks access all weekend.