The trail dips and dives through the coulee, along the heaving banks above the mighty Oldman River, and I've got to have my “A” game. One wrong turn, one tactical error, and I'll have a close encounter with thistle and sage. Or, worse, prickly pear cacti. Or, much worse, a deep ravine. The trail could be anywhere in southern Alberta, I suppose. But the backdrop – the longest and highest trestle bridge in the world – is a dead giveaway.