Until 1992, the 1,400-mile Alaska Highway featured a dearth of fuel, people, and pavement. These days, though, the road is mostly blacktop. Which means you don’t need three spare tires and the best adventures are found off the beaten path. Pick your detours using the route’s mile markers, which start at Dawson Creek, British Columbia, 810 miles northeast of Seattle. At mile 497, stop at Liard River Hot Springs, where a boardwalk takes you to a 107-to-125-degree pool. At mile 805, fish the Teslin River for Arctic grayling, lake trout, and salmon. (Guided trips, US$60 per hour with Nisutlin Outfitting; nisutlinoutfitting.com.) The highway is also home to a raft of renowned lodges. Our pick: Northern Rockies Lodge, with its chalets alongside Muncho Lake, at mile marker 462 (doubles, US$270; northernrockieslodge.com). The best hiking? You’ll find it in the Yukon’s Kluane National Park and Reserve, at mile marker 1,053. Try the Bullion Plateau Trail (15 miles round-trip) from the Tachal Dhal Visitor Centre for a spectacular day hike with views of the Kaskawulsh Glacier. Once you cross into Alaska at mile 1,221, it’s all big peaks (check out Johnson Glacier in the Alaska Range), caribou (Tetlin National Wildlife Refuge hosts the 30,000-head Nelchina herd), and braided rivers (the Tanana Delta is cold and not suitable for tubing). Once you reach the end of the road at Delta Junction, it’s a 390-mile drive south to Whittier, where the five-day ferry (from $2,340 for two, with a car; akmhs.com) back to the world—or Bellingham, Washington—awaits.