Blair Braverman harnesses her dogs at the Tustemena 200 race, a qualifier for the longer Iditarod. "It sounds simple, but the biggest challenge for me in Iditarod this year is that it's new. I've never run 1,000 miles with my dogs before; I don't know what that looks like. I haven't experienced the trail. I haven't been sleep deprived for that long before. So I'm essentially launching into a huge unknown. That sense of not-knowing has defined all my training, all my preparations."