Use some common sense and you shouldn't have too much hassle.
Cities and large towns are where you are more likely to have trouble parking.
There is a RV Friendly town scheme :http://www.cmca.net.au/pages/motorhomin ... Towns1.php
Not a huge amount of towns so far but if one is on your way,
you can feel more comfortable that you will be welcome there.
As already mentioned there are plenty of Free/Low cost camps along
the way and the Camps Australia Wide book has many of them listed.
When you stop along the way, be friendly and don't be afraid to ask other travellers
about good places as they may have recent knowledge of the good and the bad spots.
Information centres are very good places to find out what is available locally.
Plan ahead or stop early enough in the day to find a suitable place for the night.