Hi Fahim,
We camped in Goobang NP in Feb and visited Peak Hill on a day trip. Five km out of town on the Tullamore Rd is a small reserve at Bogan Weir. I expect you will see some light from town but it should be OK looking west. We were there in the afternoon and there was some boy meets girl activity happening: car load of young lads arrive and red-P driver attempts some hooning in an underpowered diesel crew cab ute (lame). Ten minutes later a car load of young women (red-P) arrive and congregate with the lads at the far end of the reserve. I expect you would have the place to yourself at night but if they are still there they will probably be quiet
.
If you want to drive further try going past Tomingly and take the right onto Gundong Rd. From there it is 18km to the entrance to the NP. Enter the park but don't go right to the camping ground. Stay to the left and you will be on the eastern boundary road - it's wide smooth and flat. Go a km or so, to clear the camping ground, and find an open spot. Nothing but roos and possums to disturb you out there.
Otherwise there are plenty of quiet roads close to town. I expect that the area around the disk will be lit up like a xmas tree. Radio astronomers don't need dark skies.
Enjoy your trip and I hope you get clear skies.