In general, unsealed road in outback = need 4WD, depending on time of year. Often needs expert 4WD driving. Be aware that if you are stranded, and need a tow truck, that will cost several thousand dollars unless you are in designated areas, then there is an additional fine of $1000 per wheel (so $4000 minimum). Not sure if that applies on this route, but it happened to someone I know (cost over $10,000 for retrieval of his car and caravan). The sealed road route should be pretty sedate and no problem, unless there is flooding involved (deserts get the worst floods).