If you want to see the areas like where Crocodile Dundee was set, that's way up north.

If you like tropical, then Queensland is probably your best choice.

If you like some bushland, ocean, etc., then south of Perth, Western Australia might work for you ... or perhaps the Adelaide area.

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"Cheap cabin" ... the lowest you'll likely find is $70/night, but unfortunately those are getting rarer all the time. Most tend to be priced around $100/night. But look up caravan parks. The least expensive indoor units you'll find in caravan parks will be onsite vans, if they are available. Those might run as low as $50/night, especially in August, but sometimes they are more.

Also look for hostels and backpackers.

South West Hostels | Backpackers | YHA Australia
For example ... you might cycle to or through several of the places in the above link if you go south of Perth.

Cairns Hostels | Queensland (QLD) | Backpackers | YHA Australia
And the above link are the hostels in Cairns and northward.



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As for weather, here's one of the sites we use, and this is for Albany, Western Australia:
Albany weather - local weather forecast

Have a look at the averages page:
Albany climate, averages and extreme weather records

Or if you prefer warmer, here's Cairns, Queensland:
Cairns weather - local weather forecast

And Cairn's averages:
Cairns Ap climate, averages and extreme weather records

And just for reference, here's Adelaide, South Australia:
Adelaide weather - local weather forecast

And Adelaide's averages:
Adelaide climate, averages and extreme weather records