maps or GPS
Hema maps cover the country with maps scaled to show a high enough level of detail for your average bike tourer. They are common enough in newsagencies, camping stores and roadhouses but sometimes the local map can be sold out needing some fossicking to locate.
There are Hema regional maps: Kimberley, Flinders Ranges, Top End etc. These are often annotated with a brief description and history of some of the local features.
The Hema Great Desert Tracks series are 6 maps of Central Australia covering the more remote country at a scale of 1: 1,250,000. These are great to show the usual things: the class of the road/track, the size and location of settlements and the station homesteads. They also show information not shown on other maps: community store or roadhouse opening hours; extent of sand dunes and their direction; often water tanks, waterholes, boreholes etc. If you are heading up the Tanami or traversing the Great Central Road it’s all very useful information.
There’s a couple of specialised map sets for the long distance bike trails: the 900km Mawson Trail from Adelaide to Blinman in the northern Flinders Ranges in South Australia and the 500km Munda Biddi Trail from Mandaring just east of Perth to Nannup in Western Australia, (as at 2010). Google is your friend to track them down.
GPS with a decent 4WD map set is fantastically useful if you need that much detail. The downside of most units is the pathetic battery life which can be frustrating when it’s a week between power outlets. You will need to travel with a solar recharger.
But you already knew that.
If you stay for a while in the capital cities there’s usually a map of the local bike paths which can make it easier to get around.