Hi desmodus,
I am Australian currently living in UK, but know Brisbane and Sydney and a bit about going north and south from there.
When you arrive in Brisbane or before check out www.gumtree.com (a worldwide website you need to change the city so you connect with the right place) for instance http://brisbane.gumtree.com.au sale of campervans or cars whatever is your preference you can sometimes find a good deal other travellers going home for Christmas and now selling the campervan they used to travel the east coast during winter months.
Also check out RACQ in Brisbane, Queensland for travel maps and all kinds of camping grounds information also NRMA in New South Wales.
GET loads of information from tourism Australia this website http://www.australia.com
Places of interest on the way north – Sunshine Coast (Steve Irwin – Crocodile hunter – country) – Hervey Bay & Fraser Island (World heritage-listed largest sand island in the world) – and of course Whitsunday Islands, Great Barrier Reef.
Then south from Brisbane – Gold Coast – and in New South Wales a must see Byron Bay (Cape Byron most easterly point of eastern Australia – and also where I am from – a melting pot of surf culture, alternative philosophies and hedonistic indulgence – make sure you are there for a Sunday market at The Channon (2nd Sunday of the month) or Bangalow (4th Sunday of the month) Byron market is on 1st Sunday of the month – however Channon and Bangalow have a better location amongst the trees and a better vibe – be around for the afternoon drumming which takes place from about 3.30pm and join in the dancing) OK enough about my favourite place on this earth.
Heading south towards Sydney some great places enroute, mainly coastal towns, whilst in Sydney do the must see icons and definitely go up to the Blue Mountains check out Wentworth Falls, Leura, Medlow Bath and Mt Wilson – and Jenolan Caves – http://www.visitbluemountains.com.au
Be prepared for warmer weather and humidity whilst going north and also possible rain, have loads of mosquito repellant coils and get some natural mosquito spray-on repellent for use on yourself and the kids – available from good pharmacies and “Go Vita” health food shops, heaps of sunblock, aloe vera for sunburn relief, and “Stingose” for the treatment of bites and stings from wasps, bees, nettles and other stinging plants, mosquitoes and even jellyfish. Wear sunglasses and hats all the time the Aussie sun is strong you will burn quickly.
Apart from that a great place to visit and loads of seafood to be had on the way and exotic fruits.
Enjoy guys you will love it once you get past the creepy crawlies. LOL