The Boreline Road north of Roxby is usually maintained pretty well, but it is gravel, of course.
Likewise the Oodnadatta Track and the William Creek to Coober Pedy road..
Slow down and reduce your tyre pressures and you should be fine.
You will collect some dust though

On the RHS about halfway between William Creek and Coober Pedy is a PAR (Public Access Road - read "track") towards Lake Cadibarrawirricanna (the longest place name in Australia, I think :) )
There is a channel that follows the track north to the lake that has some good lunch spots along it. There is almost always water in the channel.

EDIT. Coward Springs is a commercial camp ground and very different now than years ago.

Taken in 1970 (in a Mini, so you will be fine  ) with the Ghan going past.

Berrisford Siding is one of our favourite camping spots. No facilities, but the old railway stuff there is great.

Cheers,
Peter