Take the footpath on the right hand side of bridge, ie the northern side. When you get to the Huntley Point end there will be a fence that turns you around. Now you have 2 options;
1. Cross the road at the end of the fence and ride along the dirt on the right hand side until it takes you within some armco, where you join a footpath that takes you all the way to the Hunter Hill overpass.
2. Go down the staircase that takes you under the road, turn left and keep left going onto the footpath that appears to your left, it will take you up a short steep hill, where you will join the same footpath that takes you to the Hunter Hill overpass.
http://maps.google.com.au/maps?hl=&q=gl ... 2&t=h&z=20