Hi Duncan,
to IIS,
You might like to contact some of the local astro clubs to see if they may be able to help out a Yankee visitor go bush,
There's a few clubs to ask:
Macarthur Astronomical Society Their observing sites (2) are towards Southern Sydney.
Astronomical Society of NSW Also have a couple of observing sites, one about an hour and a bit from Sydney's CBD and another about 3hrs west.
Northern Sydney Astro Society Sydney based with only an observing site in Northern Sydney, Terry Hills, but it is the best Sydney based site I know of - I was there just this last Saturday and I saw the Coal Sack for the first time in years from Ol' Sydney Town!
Sutherland Astro Society Another Southern Sydney based club with a couple of remote observing sites.
I'm sure you'll be able to find some sky time with these fine groups,
I apologize if I've missed out on any other astro clubs. I'm sure they'll say g'day, and give me grief...
Alex.