There also are a lot of journals that make use of the free campgrounds as saddlesores mentions.
Why not do both. There is not requirement for you to camp out every night. But motels can become expensive and rather solitary. They might be handy when you are wet, tired and cold and not camping in small town parks or commercial campgrounds are available. But that bugdet can take a beating, when it could be spent on other little leisures and pleasures.
I gather you will need to understand that caravan parks here in Australia are a little different from the RV parks in the US.