We are often asked what is needed to travel Australia, or what we use. There are three answers to this question:
1) You don't need anything to begin to travel - you simply won't be able to see everything you want to without the right equipment though.
2) It is essentially impossible to see everything, but still travel comfortably. If you want a toilet / airconditioning / lots of water etc. -- then you probably cannot get to some places. Alternatively, if you want to see something 'off the beaten track' - then you probably cannot get your palace on wheels there.
3) Our kit. Our kit is intended to be flexible. We like to go to an area (generally on good roads), camp up, and then explore for a period (often on not so good roads). The camp up, is generally our Bushtracker caravan, but can be a tent for up to a week. The tow vehicle is a 4x4, partly due their ability to handle water crossings, mud and sand - but also due their towing ability.
The Unimog. We have a whole page devoted to this.