i am not `sure about advance booking for caravans but for rental accommodation we paid a bankers cheque, it is like a draft. if you egt it made from teh bank they charge 10$ each and i think online it is 5$ each.
why not try hostels? i heard they are cheap as well.
ACS assessment : May 2008. Visa Application VE 175 : September 2008. State Sponsorship : September 2009. CO Allocated : 17th November 2010. Medicals and PCC submitted : 13th December 2010. Medicals for my Daughter : 22nd December 2010. All Documents Met : 31st December 2010 (except for meds for my daughter)
VISA GRANT 27th January 2011
Reached MELBOURNE on 16th June