Family Friendly: Given that it's a walking trail there is no expectation that cyclists will be travelling at speed. As long as young riders have good brake control they will be able to comfortably navigate downhill.
The surface of the trail is predominantly hard-packed dirt, though some sections are grass covered and a few corners on the main descent are sandy. The trail is well marked and fairly clear as to where it goes. Be sure to follow this trail in a counterclockwise direction as this gives you a longer descent and easier climbs.
This is primarily a walking track and you'll often find walkers on the trail so be sure to keep an eye out and give way if you encounter someone else on the trail.
Starting from the reserve entrance closest to the carpark, stick to the uphill path. An easy climb through the trees will lead you to a forest road heading to the summit of the hill. The trail continues across this road with a slightly more difficult climb over some erosion control banks. Once at the summit, you've got a decently long downhill section ahead of you. However, take care as the corners are generally off-camber and can be sandy. The lower half of the descent has a number of erosion control banks crossing the trail that can be used as jumps. A tight, sandy right-hander marks the end of the main descent but if you can carry speed through it the next easy climb can be largely negated.
As the trail opens up and turns to your left, you'll have a great view of Bathurst and the Uni in the foreground, before starting another downhill section. The Kangaroo Walking Track
splits off to the right and is worth taking as it adds another ~2km while only skipping about 200m of the John Cousins Trail.
If you continue straight ahead, you'll find the two fastest corners of the trail, a rutted right hander that can be taken at speed leads into a slightly banked left diving into the creek before the return climb begins.
The final climb is long but fairly easy, with plenty of tree cover to provide shade from the sun for those summer rides. Once you reach the forest road you can choose to turn left and climb a short distance to do the first section of the trail in reverse but when it's busy it's best to turn right and go with the expected direction of travel.