You can traverse the Oodnadatta Track in either direction. From the north, the track starts at Marla (population 100) on the Stuart Hwy, where the Marla Travellers Rest has fuel, food and comfortable places to get horizontal. Around 209km from Marla, Oodnadatta (population 200) is where the main road and the old railway line diverged. Here you'll find the Pink Roadhouse, a solid source of track info (they're big on maintaining correct tyre pressure) and meals (try the stultifying 'Oodnaburger'). The roadhouse also has an attached caravan park with basic camping and a serviceable camp kitchen.
In another 201km, you'll hit William Creek (population six!), best experienced in the weather-beaten William Creek Hotel, an iconic 1887 pub festooned with photos, business cards, old licence plates and money stapled to the walls. There's a dusty camping ground, and modest cabins and motel rooms. Also on offer are fuel, cold beer, basic provisions, all-day meals (mains $16 to $32) and spare tyres.
William Creek is also a base for Wrightsair, which runs scenic flights over Kati Thanda-Lake Eyre (two-passenger minimum). Any detectable moisture this year?
Some 130km shy of Marree, Coward Springs Campground is the first stop at the old Coward Springs railway siding. You can soak yourself silly in a natural hot-spring tub made from old railway sleepers (adult/child $2/1, free for campers).
Next stop is the lookout over the southern section of Kati Thanda-Lake Eyre, the world's sixth-largest lake, fully protected as a national park. It's usually dry but a couple of times in recent years it has filled with flood waters running in from Queensland. When this happens (only once every decade or so), the explosion of bird life is astonishing! It's also the lowest point on the Australian continent, bottoming out at 15.2m below sea level.
Mutonia Sculpture Park – about 60km west of Marree – emerges from the desert unexpectedly. All sorts of wacky weldings stand mute in the heat, including several planes welded together with their tails buried in the ground to form Planehenge. For a preview, check out www.atlasobscura.com/places/mutonia-sculpture-park.
Marree (population 100) was once a vital hub for Afghan camel teams and the Great Northern Railway, and is the end (or start) of both the Oodnadatta and Birdsville Tracks. The big, stone 1883 Marree Hotel has decent pub rooms (shared bathrooms), smart en suite cabins and free camp sites!
The folks at the Marree Hotel can also hook you up with a scenic flight. From the air you'll get a good look at Marree Man, a 4.2km-long outline of a Pitjantjatjara Aboriginal warrior etched into the desert near Lake Eyre. It was only discovered in 1998, and no one seems to know who created it. Eroding away to nothingness for many years, in 2016 it was reploughed into the dirt…and still no-one knows who's responsible!
From Marree it's 80km south to Lyndhurst, where the bitumen kicks back in, then 33km down to Copley at the northern end of the Flinders Ranges.