Sounds like an awesome trip. I'm from melbourne and i did a similar trip last year heaps of fun. I would suggest getting a car for sure. There are vans called wicked vans i think they are about $50 a day to hire and u can sleep in them. Heaps of people are doing the same thing staying in camping areas along the way so you'll meet heaps of people. You can stay in camping areas that cost about $20 a night or you can just camp on the side of the road. Its not legal but you should be fine. the weather should be pretty good so camping will be fine. There is hundreds of places to go Some cool places to research: port stevens, port mcquarie, coffs harbour, Byron bay, Gold coast, Noosa/ fraser island ( abour an hour or 2 past brisbne but an amazing place fraser island is realy popular with overseas travellers for wildlife), foster. there is heaps more you just have to explore. I think schoolies is around the 20th of November this is when all the year 12 students (18yr olds) have finished school. Byron and the gold coast will be mental at this time of year. Let me know if you need any more specific stuff. Have a good trip!!
sounds sick mate its an awesome part of the world. im from inland and south but byron is a heaps sick chill place. good surf in that area to. if you can make it, try get even further north, like cairns and especially a place called port douglas... i mean its probably fair way out of your way but a marathon days drive would get you there... its on the great barrier reef and ive been there once and never been so blown away, most beautiful place. schoolies is around the 20th of november for a few weeks, cant remember when you said you were goin anymore but anywhere along that coast, byron and surfers especially, will be pretty hard to get accom but it would be epic as if your lookin to prey on young birds... and the parties will be epic. hope i have helped you'll have a sick time