Hey mate
We did the track in December just gone. Was heavy with larger rocks from Maree to William Creek. It was certainly better from William Creek to Oodnadatta. We didn't goto Marla however so I can't comment on that portion. I think the issue with the Ood is that its quality changes so much through out the year so best to check just before you go.
Good tyres all around required as you are probably aware. Drop your tyre pressures. Extra spares maybe? We didn't have extra spares but my father in law was getting a bit edgy when he had used his van spare and his car spare with 200km to go to Oodnadatta.
Dust Proof Van.
Seal Underneath, Seal from inside - ie I sealed the inside of the cupboards that were potentially exposed especially our clothes cupboard. If you look at the wheel arches you can probably see daylight. This is a good spot to check. I put a piece of eggshell foam in there nice and tight.
Not game to take it out yet. LOL.
A piece of foam in the vent of the expandas door worked very well. Vent covers over your vents - use a good material like canvas. Must have a tight weave to ensure the dust either won't go through or will only be minimal. We didn't put one over our fridge as we wanted to leave the fridge running due to hot days. If it is cooler, I have read on here some guys did turn their fridges off and put covers over those vents too. Have you got air con in the van? If so, where is the air intake? Mine is under the van so i sealed this too and covered it with a piece of checkerplate to stop any stones hitting it.
Our bed ends didn't get any dust but I have seen others that had. We took a heap of tape and drove for about an hour to see how much if any was going in. If there was we were going to seal it with tape but didn't need to. In saying that, we did get some thick foam tape prior to the trip and foam tape around the bed ends where I thought dust might try to get through.
Water Pipes underneath your van. I run (maybe over the top?) a piece of heavy rubber underneath all my water pipes - so basically from one water tank to the other. I think they are probably one of your most important things to protect or change plastic fittings to metal. I only got a smashed drain outlet pipe and did a temporary fix on this with some 1000mile an hour tape.
Worked a treat.
Stone guard on van of some type if you haven't already. I reckon the stone stomper is the best I have seen but don't have one.
If I think of anything else I did will let you know.
Cheers
Ants