G'day Ken,
mate i used to ride Lockmaree a LOT years ago, excellent trails, very good amenities (old house with bunks and kitchen,clean and tidy,well set up.) They , the original guys (Rob and Wayne R.I.P both) were building an MX track, but was more a grass track back then, you'd be best off ringing and speaking with the current owners whomever they are for an update. Like i say, the trails were excellent, a couple reasonable smaller hills, lots of single track but not the type you need bark busters for, some flowing over grown two wheel tracks etc. The only down side back then was a fair bit of dirt road from outside Goulbourn to get there.
Hope this helps!
Kt