Hi Jellybean,
Believe me, Don really is 'bushman extraordinaire'. We spent a week or so with him in Kakadu last year. It was a pleasure and a massive learning experience.
My experience with '100 person' is that everybody tends to drop off into the creek too soon after coming down off Cloudmaker.
So they end up in the scrubby, thick headwaters of Tiwillia Creek and it's a bit of a battle.
Better to head out onto Tiwillia plateau and head north.
Drop off into TiWillia Creek when you see a small hill rising on the inner walls of Tiwillia Plateau.
If you pick the right place you will drop down just before the cliffline starts to form and be very close to the cave.
Having said this, hope I get it right this weekend.
Looks like it is going to be cold, weather forecast is saying -4 or-5 for the nights
Will let you know how it goes, if I don't freeze out there!!!