We successfully completed our trip, check out my trip report on Kosciusko Mountain Retreat.
http://www.expandasdownunder.com/threads/kosciuszko-mountain-retreat.5495/#post-83357
In short everything went well, stayed warm with a 1500w oil heater and a 2000w blow heater going. Left the oil heater going all night.
Pipes did freeze during the night so I just filled the kettle and water bottles the night before. Condensation inside the van was significant, had to keep wiping it down.
The Aldi Ski gear held up really well, even the gloves, everything stayed dry and no complaints from the kids. First two days we had sunshine, then the next two were blizzard conditions. I have those 'Wet Seat' covers on the Jeep so when coming home we left all our gear on, on the outside it was sobbing wet, but by the time we got back to the van everything was dry, no need to put in front of the heater.
I took too many clothes. Only put on a clean shirt and underwear on each day. Kept the ski gear on when back at van and then had a shower and put on PJ's.
We had premade dinners such as curries, stew and bolognaise, so we just pulled one out the night before, let it defrost and cooked up the pasta/rice for it. We were pretty knackered each night so glad we had done this. Took up hotdogs and cup-a-soups for lunches and made sandwiches the night before. We parked and skied at Smiggins so were close to car, and saved a bit of cash by doing this.
Overall had a great time. Might do another trip down there for 3 nights again soon.