Treat named entry points as locations, not a statement of permission, and respect any fence or sign on the ground. FlyLife’s writers describe access as easy all along Buckland Valley Road after the bridge, with Buckland Bridge and Ah Youngs Campsite named as entry points.
Buckland Bridge and Buckland Junction Bridge are described as reachable in a 2WD. Campflat is more remote and needs a 4WD and some hiking, so plan that trip with more time and care.
As on any bush river, tell someone where you are going and when you expect to be back, carry water and a first-aid kit, and watch your footing on wet rock.