[boxhead]

I have driven on many of Australia's National Highways (have not been far north west)
As others have said it is all possible, although if you are wanting to go from say Perth to Brisbane/Surfers Paradise, then there is no direct route.
If you want to see the middle, there are no roads east/west, only north south.
Also traveling in the far north at this time of year there is always the risk of Cyclone and road closures due to floods.
On some stretches of road you can travel 300- 400 miles between fuel stops.
Before deciding, have a real good look at a map, one that shows town locations to see the vast distance between locations.