Crossing The Simpson

Your initial propsed route will be fine as long as your vehicles are well prepared.

Many say West/East is easier due to the dune formation from prevailing winds, however we have crossed East/West twice without any difficulty.

Regards

Easiest way is west to east as the dunes are shallower that way. Prevailing wind is westerly so dune faces are steeper from the east.
Either way is do-able, just a bit harder going from the east.
Cheers, John.

With 13 crossings over 20 years I'd reckon it doesn't make much difference these days. Yes the western sides are not as steep but are usually rougher due to the large numbers of drivers that don't drive to the conditions and/or don't drop tyre pressures enough causing opposing wallows.
In holiday periods the eastern sides are usually smoother and easier as the majority travel west to east rolling the eastern sides. If you are ever having trouble climbing dunes in peak periods wait till a vehicle comes from the opposite direction and they will have 'rolled' your track making it much easier.
What you may have in sept/oct period is much higher temps with very high 40's experienced so I would do it as soon in the trip as you can, a few weeks may make a difference.
The best route to see as wide a variety as well as avoid 'dune boredom' is QAA to Poeppels, French line to the Knolls, down the knolls track to either the WAA or rig road then west with a detour south to the lone gum if travelling via the WAA.
While you will travel a bit further fuel consumption will remain about the same due to easier travelling.
The one exception is if it rains or is wet just before you go. If that is the case stick to the French line all the way west as the clayed rig road is hard work when wet never mind the damage you will do to the track.
The French linis all sand till it hits the rig road.
Better still in wet weather, camp for a couple of days and let it dry out.

I think if you do a search of the posts, you will find many on this subject. Also see trek notes.

I think west to east across the desert is easier, especially if towing a trailer!
French line is rough(lumpy), and you'll only average 15 km/h on a lot of it. Other ways to go as well, but I haven't done them.
The Cordillo Downs track was very rough when I went through - don't know what it's like now, but wouldn't go there again.
Either circuit would be OK, but I would pick the second, also taking in the painted desert on the way to Coober Pedy, and go the back way from Ayers Rock to Alice, via Kings Canyon. We have recently travelled a lot of that area, and you could check it out at http://www.phg.com.au/staff/gw/4x4ing/index.asp

Thank you very much guys for your valued input and advice - it is truly appreciated I can assure you.

This at least gives us something to work on and can now give our trip leader some more options to look at.

Thanks again.

Regards,
BigPop aka Pete
(I never get lost because everyone tells me where to go)

BIG POP I personally would'nt do the cordillo downs track it's to rough for my like'in if your caming from Innamicka take the WALKERS CROSSING track to the BIRDSVILLE track which cames out 120 ks south of Birdsville you'll enjoy more cheer's GREENDOG