On the northern margin of the Alaska Range, just before the hulking ramparts of Mt. McKinley and its satellites surrender to the low Kantishna plain, a series of lesser ridges, known as the Outer Range, sprawls across the flats like a rumpled blanket on an unmade bed. Between the flinty crests of the two outermost escarpments of the Outer Range runs an east-west trough, maybe five miles across, carpeted in a boggy amalgam of muskeg, alder thickets, and veins of scrawny spruce. Meandering through the tangled, rolling bottomland is the Stampede Trail, the route Chris McCandless followed into the wilderness. Which line suggests that the ground is flat with some bumps and hills?