Everything that you put in your first post sounds great... but do you olan to have any time to get out of the car and see anything let alone photograph anything? Ditch the northern end and stick with the south if that's your starting game plan. The drive from south to north has inspired many people to stop travelling. Adelaide to Alice is approx 4000km.

The great Ocean Road is a must do for a road trip and you can drive it all the way to South Aust if you want. Then there's Halls Gap. Depends what you're into anyway. Adealide is a beautiful place and with NSW tags you'll be safe from the Vic haters. (which is about 75%)

Hanging Rock is a nice place too and if you are up for the Nerve test.... You will be able to photograph the crap coming out your pants.