The Australian continent is HUGE, so unless you have infinite time you must limit your your itinerary and it’s going to cost you to get around.
Planes and car hire are the most time effective way to manage Aussie holidays, but travelling long distances to some places expecting an interesting, lively culture and finding a dull, shopping mall and beer dominated town can be depressing.
Accommodation is not especially cheap, though you can easily rough it on a budget and the East Coast in particular is well set up for backpackers.
Winter (June – August) is frequently chilly for New South Wales holidays in the south, particularly if you were expecting to spend your days in a swim suit, though Queensland will be perfect then.
The country’s deadly critters require care and Outback flies can be incredibly persistent and irritating while leeches, ticks and mites are not uncommon travelling companions. But, get there in the right season, with the right attitude and you’ll love the place.