This entire season is a bad idea.
I'm also quite concerned - I honestly don't mind the idea of an Australia-only season but I wish they waited a few months until the whole country is back in action.
Both WA and Vic are completely off limits (and Tasmania is only letting residents in). Therefore, the route will be poor with just NT, SA, QLD and NSW? Not sure about ACT.
Considering they are supposedly doing a two-week quarantine first, I'm tempted to speculate a start in the NT - perhaps even where Season 4 finished off in Katherine Gorge?
Then down to SA and then across to QLD, finishing in Sydney, NSW perhaps.