I went there years ago and checked out vulture wall and a couple of other areas nearby. I can't remember where I got the guide from (I thought it was canberraclimbing.com but it isn't there now so ??) so wont be able to help much. For Access you park a few hundred metres towards the coast (away from Nerriga) from the cutting near a gated road which heads off up and at a narrow angle to the road on the south side. Cross the gate and head up the hill on the access road till you are underneath a high voltage power line. Head down the road until a small cairn appears on your left then bush bash about 50m to a narrow small gully which from memory might have a chimney move or so in it. There should be a rusty old carrot on the wall on the left (facing down). At the bottom of the gully the Gym area is to your right whereas the majority of the other climbs are to your left. Head to Vulture wall for some low to mid twenties pumpy longer routes or there are a few nice slab routes about 100 m further on. The gym has routes in the low to mid twenties and is short and very pocketed (hueco style).
I hope that helps. My memory could be a little rusty. The walk in is about 10-15 mins from the car.