The way points of this bicycle route:
Starting at the Visitor Information Centre, ride West along the bicycle path beside the creek.
Take bicycle path up to Donnelly St and ride across the bridge.
Last 2 and a bit km is shockingly rough corrugated gravel road. Turn around at the end of the bitumen unless you have really good suspension. Otherwise, Dumaresq Dam itself is quite nice with a BBQ area and playground for the kids.