In the Halton Hills on the outskirts of Georgetown, a section of the Credit Valley Footpath links an old paper mill to an old hydro station. This rugged two-km stretch follows the gorge created by the Credit River, sometimes high on ridges, sometimes low at water's edge. Steep ups and downs--with as much as 40-metre-high climbs--are often, thankfully, accommodated with log steps, and bridges span many--but not all--feeder streams and ravines that cut across the undulating embankment. From one ruin to the other, you're led through forest, under a railway trestle supported by massive stone towers, following curves...