In general when undertaking any trip it is your responsibility to have up-to-date maps, information and appropriate, serviceable equipment. Tell someone of your travel plans and expected return date, and provide contact details in case of an emergency.
In national parks, keep to the walking trails unless you are experienced at map reading and navigation. Always ensure you have the necessary permits for the area you will be traversing and be aware of any warnings issued by relevant authorities such as National Parks and state forests.
If you are going off-road or into any remote area always check for road or track conditions and inform someone of your trip plans including return dates. If traversing remote and rugged areas it is useful to have another vehicle to assist in recovery operations or serious breakdowns. Carry maps, adequate communication and navigation equipment, safety gear including a first aid kit and extra water. A registered Epirb (personal distress beacon) and/or a satellite phone are advisable for remote area travel.
Remember just because you are in a 4 wheel drive you are not necessarily bulletproof. Before going off-road make sure your vehicle is suitable for the conditions you will encounter, mechanically sound and appropriately equipped. Learn the limitations of your vehicle and improve your off-road driving skills by undertaking an off-road driving course or jining piggy back off road trips with our wheel drive clubs. You are responsible for all of these and for the safety of any people accompanying you.
Last but not least you are responsible for the application of common sense.