Jeez fella's talk about blow it out of proportion, he's not crossing the Simpson Desert!, The Oodnadatta Track is a very well travelled road, most, if not all the sights on the Ghan line up to Oodnadatta are on the road, The Oodnadatta Track swings West after Oodnadatta to join up with the Stuart Hwy, the road does continue on thru Finke but it is never in a good condition and enquiries should be made at Oodnadatta. I do have to agree with some comments regard weather, don't go in summer -it's too hot and you'll get bogged in dust, don't go in winter -it can be too wet and you'll get bogged in mud and Autumn can be dicey with unseasonal rains. Spring is the best time, I assume you are taking a 4WD? the trip can be done in a 2WD car (been there, done that) but if the previous season was bad and the roads haven't been graded you will be in a spot of bother, go 4WD to be safe.
If the rains in Queensland have been good you will have to go out to Lake Eyre, ask at William Creek pub, that is one trip you will not want to do without telling somebody, people have died going out to the lake, don't take that trip lightly.
The rest of the trip should be a breeze (weather depending), most sidings are nothing but dust, but check out Curdimurka, Strangways Springs (I think this is the one with the railway dam right by the station), William Creek, Stuart Creek bridge, Algebuckina Bridge over the Neales River is a must see. It has been some years since I was up there but I presume some Desalination plants are still standing in some yards, there are probably other sights that have escaped my memory.
And not forgetting Quorn, Hawker, the Puttapa Gap detour, Beltana and Farina before you get to Marree.
It is not a dangerous trip but road conditions can vary wildly from one season to the next so enquire with local authorities (police) and seek advice from the RAA or equivalent before you go, be aware that what is nice today might be impassable tomorrow no matter what the time of the year.
The only accommodation/fuel beyond Marree is William Creek and Oodnadatta if you want a bed, camping out can be good (Wolf Creek is only a movie LOL), but nice spots can be few and far between, as it has been some years since my last trip I can't comment on the state of ruins etc for camping, make enquiries and plan carefully is all I can add.