Hi SB,
Check out Wollongong (YWOL). About 1.5 hours south of Sydney, plenty of parking for both your van & Cessna. Two sealed runways, great on-site restaurant, flying school, aviation museum (full of engineers) and the State Fire Brigade, Rural Fire Service & Ambulance Helicopter operate from the field. These services have staff coming & going 24/7, so it is a fairly secure location.
You'll find plenty of helpful people there, it's an uncontrolled airfield (CTAF) and is situated in a country setting with the coast just a few miles to the east.
Check out this link:
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Good luck