Maps

Geoscience Australia provide downloadable topographic maps

50k Map Index, most from northern coastlines, minimal others
100k Map Index, most coastal regions excluding Tasmania
250k Map Index, complete coverage
1 Million Map Index, complete coverage

The Federal Government's National Maps is a useful online topological map with lots of additional data providers like the SRTM 1 sec DEM data set.

New South Wales (NSW): Free PDF downloads or browse online. Mostly 1:25K, some 1:50K maps.
Queensland (QLD): An online tool QTopo that allows you to generate custom topological maps. These do lack some important details like the map's declination.

It was difficult to accurately navigate using the maps for Condamine, Balonne and Culgoa rivers due to the frequent twists and turns and complete lack of things to take a bearing on. A GPS device is strongly recommended as an additional navigation aid if you want to accurately track your progress.

Condamine Maps

Balonne Maps

Culgoa Maps

In high flows, the river covers the floodplains. Navigation is mainly based on tracking the river gums. I found it best to check my GPS when the river split and the main channel was difficult to distinguish.