If you head down Bibbenluke

If you head down Bibbenluke Track, insead of going straight down to the water you can take the track to the left, it goes down the hill and across a creek (when the weather is good) although there are big flat rocks so its nice, then up the hill where you will come out behind the Duffy's Forest Bush Fire Brigade - to the left is the way back out to the road - you will have the public horse arena on your right. Or, at the top of the hill you can turn right and go around the back along a fire trail - there is only one interesection where there is a little single track which winds back to the fire brigade, or you can stay on the fire trail which takes you back out too.
When you reach the road go straight ahead, turn right to go to either the Sandy Trail or right and left to go along the road back to the shops etc...
Hope all that makes sense, you can do over 40ks in Terrey Hills without really back tracking - you can ride up to St Ives Showground through the bush and to Ingleside...