Jim "Yeti" Fulmis, 79, and Melanie Simmerman, 63, on North Cottonwood Creek Trail north of Bozeman. The married couple is in the process of hiking the circumference of Idaho. In 2010, Yeti blew out his knee on the Pacific Crest Trail, 580 miles from the end. He says he gutted it out, bone on bone, 100 miles to Ross Lake, then had the knee replaced and finished the trail the next year. Toenails are frequent casualties to long hikes, Yeti says.