Hi Bernie,
I'm sure you will get a lift from someone going up, either at Katoomba or Medlow Bath. On the Wednesday or Thursday prior we should have a fair idea whether the weather is going to be ok or not. If it's doubtful the go/no-go decision will be made by midday Saturday.
In the morning I suggest better to get a lift back to Sydney or to Katoomba and get a couple of hours sleep on the way, easier than trying to sleep out up there - it gets down to 4 degrees overnight if it's clear.
Train timetable:
http://www.sydneytrains.info/index.h...1#landingPoint