Get the Lonely Planet book on traveling in Australia.
Customs/Immigration may ask where in general you are going, but that should be about it. Once you are in country, they couldn't care less, as long as you leave. I did some traveling there many years ago, but little camping. I stayed at youth hostels in the big cities, got around by bus or car.

As already said, this isn't a travel website, so get on Google and look for some-they are out there.