Have to agree with the fly as opposed to driving!
I drove from Adelaide to Darwin in 47 hours in a Hiace, with the dog! Worst drive ever, I think the largest distance between towns was around 200km's, with no phone reception, damn optus!
Do not drive at night! lots of the roads are not fenced and livestock just wander anywhere they feel like, mainly the left hand side of the road, behind crests!
I never realised just how vast and isolated this country was until driving across it.
And you will love the price of petrol in some places