First thing you could look at is
DarkSkyFinder for some of the best locations.
I am a visual observer so I can only comment on the quality of the skies in general - but what else matters really...?
Camping is the way to go if you can manage it. If you can't, then get yourself a room at a motel in a small town well away from rural centres (again the map above will help you find good locations). I assume you will be hiring / getting a car of some sort. You'll really need one if you want freedom to choose where you go.
While we have a lot of light pollution free areas in Australia, it's a pretty flat place, with not much in the way of high altitude sites (and the few modest mountains tend to have cloudier skies than other sites; they're not high enough to get you above the cloud cover). I camped out for weeks with several telescopes at places like Falls Creek but the skies were never as good as I've experienced at low altitude dark sites south of the Dividing Ranges or near Wilsons Promontory.
I might be wrong about this, but in recent years it seems to me that transparency is not as great as it used to be ~10+ years ago. Seems like there is more moisture in the air that condenses out as the night air cools, reducing transparency by 0.5-1.0 magnitude compared with the best skies I remember from the mid 2000s. But these are just personal impressions from my limited experience so don't take them too seriously. I'm just putting it out there to see what others reckon.
In any case though, if you're coming from an even only moderately light polluted area, you will see some amazing skies in Australia.