Yep, I’ve been there a number of times, and was last there a few weeks ago for what they call their tarmac weekend. They run the engines on some of the aircraft and also have tours through the place.
We sat in the F-111, had a tour through the Connie, a Dakota and also a very interesting one through the 747 by an ex Qantas captain who had flown that particular aircraft numerous times. A really interesting bloke who knew seemingly all there was to know about it.
Like you say, the volunteers are extremely dedicated and a lot of them ex Aircraft Maintenance Engineers from the airlines and Defence Forces.