Not sure what your age and obligations are, but I did this years ago. Highly recommended.
I spent time kicking around, had a work visa through BUNAC[0] but didn't use it, went to some festivals, did some WWOOFing[1] and hiking and climbing. Also took the opportunity to visit other countries near AU that I wouldn't get to otherwise (NZ, Fiji).
One of my life highlights. Two thumbs up! I doubt my experience is super relevant any more, but feel free to send me an email (address in profile) if you want to chat about it.