My suggestions would be:
Burraga Dam. Free camping, Pit Toilet, Fresh water in the dam. OK for Dogs.
Tuena. I believe there's free camping in the park or common in Tuena. Might be near the pub I think.
Glen Davis. There's fee camping in the middle of the "town". There's showers and toilets there and a community run Kiosk. Might be a few too many trees for astro work though.
Bylong. There is free camping in the showground across the road from the general store. Toilets, showers, 240V power available for free (donations welcome). Wide open views of the sky.
The attached`map from Google Earth has the light pollution overlay on it so you can see what its like. Probably doesn't matter a heap with the moon up. There might be other darker further out but I don't have knowledge of them...
Enjoy,
Al.