Hard question to answer Keith, because there's so much to see.
One thought is Sydney, Tibooburra, Innamincka (Dig Tree, Wills & Burke), Strzelecki Track to Maree, Oodnadatta Track with a side trip to The Painted Desert & Lake Eyre, The Rock, Boggy Hole, Hermansburg, Palm Valley, Alice, Old Ghan Railway to Finke, Mt Dare, Dalhousie Spings, Birdsville, Quilpie, home.