Ask to camp you car, van in at a farm, or even in someone's drivewayWhen road tripping in your van or typical Australian car (see elsewhere about car selection), you are well advised to approach home owners in middle and low income areas for use of yard space. You won't always be successful or well accepted, but you can expect to be politely dealt with even if they decline. The best idea is to look at the house for tell tale signs of acceptance. Things like open front doors, cars in the driveway with the windows down. This is common in Australia as our personal and home security is so good. Its also a good sign that the people / family inside are a little open and welcoming. Naturally the opposite of this is high fences, locked gates is indication that unplanned visitors are not very welcome. It is typical also that people that live at the beach front or have a big house with a view are a little less likely to share.
There are a lot of good examples though. There are plenty of stories around of backpacking girls with car asking at suburban homes for a safe place to stay. Similarly farms or people with acreage (large blocks of land) have lots of space and more likely to share.
Australians are friendly and care about safety for our young visitors, so the natural response from most is to permit the stay over in driveway or yard space. Using the word "safe" in your request is a good idea. Like "We are looking for somewhere safe to stay for the night."
Be careful for what you wished for as you are likely to end up with a dinner invite and have to play with the kids, pets, etc. Such stays can go on for days.
Asking for driveway space is particularly useful in locations where camping in the street, beach front, or at parks is outlawed and checked on by rangers. Hot spots for rangers waking travellers in the early morning include:
Byron Bay, NSW
Airlie Beach, Queensland
Great Ocean Road towns, Victoria
Monkey Mia, Western Australia
This is a method for obtaining accommodation that should be used more often.