Hi Iain,
I agree with Joe, I would have a search around on Google maps for a cleared area near a road- say in the Columbey National Park, just to the west of Clarence Town. Assuming you can drive in there after dark, there is a spot just here: just off "Gough's Trail"; coordinates -32.573333, 151.745071 as an example. Check it put in the daytime, and make sure there are no potential lights nearby or trees that will block your preferred line of sight...
There are lots of parks north and west of Newcastle!
It is always good to have an "observing buddy", especially if you are going off the bitumen a bit. It can get a bit "spooky" on your own (it is amazing how many things go "bump" in the night when it is very quiet!), and it gives you a bit more safety.
Check out the local Astro Society as well (see:
http://www.iceinspace.com.au/clublistings.html and
https://www.facebook.com/newcastleastrosociety ): they may have an observing site.
All the best,
Dean