Certainly would be a good half way point Dave, I can vouch for the skies being dark in Mansfield. But as Geoff pointed out fog this time of year is a concern and that area is notorius for them,
otherwise it sounds like a pretty good deal.
I also thought of another place that both Vic & NSW IceInSpacers could consider later in the year for a get together.
http://home.goulburn.net.au/~magellan/