There's several ways that I can think of off the top of my head to go camping without a car [some already mentioned]:
+ Bicycle + on-foot trekking;
+ Going with someone else and joining their car;
+ Group bus;
+ Having someone drop you off and pick you up at a designated spot at a designated time if you prefer solo camps.
Here looks like a good guide for mild Australian temperatures, including a list of minimum required equipment: http://www.bushwalking.org.au/FAQ/FAQ_U ... weight.htm
Some of those lightweight tents are pretty nifty, I remember trialling a few while I was looking for a tent
It's a good idea to bring along a radio so you can call for help if needed, and also letting someone know your schedule ahead of time if you're going alone, so that if something happens they can be alerted.
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