We are completely flexible and will be heading all over hopefully so we'll look into anything that sounds interesting.
I haven't read #1. Do you plan to be here for 12 months, or 24, or some other period? During your time here, will you be seeking work? Are you purchasing a vehicle, and if so, will it be something to sleep in? Buy a cheap GPS when you arrive (ebay, or discount electrical store) ... buy a good camping/caravanning atlas.
The whole country has worthwhile attractions ... we do not have soaring glacier-covered mountain ranges, mighty rivers through huge jungles, or millennia-old ancient cities ... Australia is a SUBTLE experience. Done in the right way and it can be very exciting and life-changing.
Avoid the tacky ... look for the natural. But also do not neglect the cities ... we actually do urban areas pretty well - our cities are nice - much better than North America, and other than historical centres, even better than many congested European ones, and streets ahead of Asian nightmares.
Eating in Australia can be cheap and excellent (especially if you self-cater) - the range that is always "in season" is staggering. Buy all your alcohol in a discount warehouse ... a quarter the price of buying it in a bar or restaurant. Get an Esky (an insulated cooler for drink and perishables).
Do not neglect Australia's Indigenous history or heritage ... it is 65,000 years old and deserves our interest and respect. Many national parks and a wide range of other places have a strong Indigenous presence ... enjoy it all.
Flock to our beaches ... Australia does "coastline"better than any other nation or continent - and by a margin that is huge. So take advantage of warm waters, warm climate, and stunning seascapes.
Do not neglect the North ... and I don't mean Brisbane, which is "south" ... I mean the half of the country north of the Tropic of Capricorn that runs through Carnarvon, Alice Springs, and Rockhampton. It is stark, unique and accessible.
Tours and activities are expensive ... so DIY as much as possible, but do take tours when it's the only way to see something outstanding (Great Barrier Reef, or Yellow Waters in Kakadu NP, for example).
Use our extensive network of caravan parks (also called holiday parks or tourist parks). The YHA hostel network is also excellent - worth joining HI now. And do consider camping - the weather is great and tent sites are cheap.
MOVE WITH THE SEASONS ... this is the best advice.
Perth in October means travelling anti-clockwise. Cross the Nullabor Plain before the end of November | Victoria | Tasmania | Sydney for New Year's Eve | Northern NSW and Gold Coast by Feb-March | Cairns by May | Darwin June | Alice Springs | Kimberley by July-August | WA West Coast by September | return to Perth by October.
Yes - in your time and with a vehicle, visit Wilpena Pound in the Flinders Ranges ... some of the oldest rocks anywhere (although the very oldest rocks on the entire planet are at Jack Hills - inland from Ningaloo Reef - they are 4.4 billion years old, formed barely after the earth cooled).
Visit Ningaloo Reef - it's easily in the Top 5 in Western Australia. When you're heading to Monkey Mia, do stop at Hamelin Pool to look at the Stromatolites ... some of the oldest living things on the planet. Australia is interesting.