Gidday Metalman,
We have done the South Aus trip the previous 3 years in our J230 and loved it ( 2009,2010,2011, damn I missed last year) with a different route each time.
One that may suit you is once you hit Broken Hill, actually before then you must drop into Lake Mungo for breakfast or lunch, great spot and people. You can do that from Swan Hill then Broken hill after your stop.
Next leg was across Lake Frome ( great sites) to Arkaroola and stay the night , fuel is available, then onto Marree.
From Marree you can go to William Creek or Coober Pedy which is a great place to overnight in an underground motel, then up to Oodnadata and beyond.
These should be easy legs. Not sure on the unleaded as we use Avgas in the 230 but they wouldn't be hard to check.
Pm Me if you want to have a chat anytime
Terry