Great report and piccies, nice for this former Nhill bloke to see!
I grew up on a wheat farm there, family still there.
Your only chance of that sand firming up is when it is saturated wet - in that part of the world that means 2 or 3 days a year. Maybe.
It's great fun on biggish 4 strokers - your WR/CRF 450's and stuff. But on heavier adventure bikes with touring load forget it unless you're a super strong and super confident rider.