We went from Yass to Rockhampton via the Newell recently.
We used a very old Camps 1 and 'Camping in Australia' by Cathy Savage. The thing I like about Cathy's book is that it does have a lot of free/cheap sites in it - mostly national parks and state forests. The latest edition is here http://www.boilingbilly.com.au/store/vi ... dProduct=8
On our trip we stayed at van parks, national parks and with friends and rellies. For 14 nights away from home out total accommodation bill was less than $250. We camped 8 and 'sponged' the rest.
If you want some more details give me a shout.