I'll be heading along for a looksee. Not likely to be taking a vehicle as there won't be much registered in our household other than the family Tarago and a 500,000km old Hiace with a Commodore V6 in it.

As to whether it's an event worthy of a 6 hr return trip it's hard to say. There's usually a decent number of vehicles there but it is a very relaxed affair. I'm not even sure if they do trophies or anything. It's just a nice Sunday lazing in the park and having a chinwag with members of the other car clubs. If you had something else to do in the area to make a full weekend of it it would be worth it but hard to say if that was the only reason you were coming.
I've got a wedding to go to on the Saturday, otherwise I'd suggest dinner somewhere on Saturday night.

As for accommodation, I've had a good experience here.
http://www.theparklands.com.au/
Booked a 2 beddy apartment on Wotif at a special rate of $250ish a night. Nice apartments with underground secure parking and an easy walk to the Dickson restaurant and bar region.