When Carolyn and Santi Ocariz clicked into their rollerskis slightly more than two months ago, neither really knew what they were in for. The Wisconsin couple heard plenty of stories about the places they’d travel through. They took to heart the warnings about crazy drivers, snakes and treacherous temperatures while crossing America’s heartland. It might not be hot when they left, but it could get brutal, and the elements could change 180 degrees by the...