[Wavytone]

Earl, there is plenty of accommodation in Blackheath or Katoomba listed on Stayz, some with the number of beds you need. The observing sites and Katoomba Airfield/Mt Blackheath/Hargraves are all a short drive from there.

Over the years I have stayed in the Woolshed cabins (in Centennial Glen, very nice), The Potters Cottage (also in Centennial Glen, very rustic but fun for kids if you are ok with animals and everything creepy-crawlie), several cottages in Blackheath (comfy and predictable).

Further afield some other "really dark" sites for observing are:

Hassan's Walls, drive into Lithgow then up Hassan's Walls Rd to reach the ridge. Excellent spot. B&B's in Lithgow.
Rydal showground (Rydal is a small hamlet near Lithgow) or Lake Lyell;
Whispering Brook Winery in the Hunter valley near Singleton - has nice accommodation for groups, food and wine tasting by day, observe by night (if you are sufficiently sober);
Lake St Clair, which is 30 minutes drive north of Singleton, this has an excellent camping ground. Plenty of spots for a 'scope away from the people. Further north up the road is also a farm that provides accommodation for groups, or stay in a B&B near Singleton.
Jenolan Caves - there are a few cleared areas along the road before it descends into the valley. The non-stargazers can stay at Caves House;
Barrington Tops, stay at one of the guest houses in the area or in Gloucester.