You would not be able to bring your possessions with you. You could probably have certain items shipped to your new rental home afterwards
nudge nudge!
You either need to show proof of onward travel (return ticket or cheap ticket to Australia
) as well as proof that you can support yourself to the tune of $350 per month of your visa. If you have no onward travel booked then you need to show proof of funds suitable to afford a ticket.
Just tell immigration you're there to travel the islands and pick up work here and there when you like. I'm pretty sure Immigration are perfectly familiar with under 30's using this Visa for this purpose. Remember that the visa terms state the 'primary purpose for the visa is holidaying'.