For Tara Geraghty-Moats, nothing compares to the sense of weightlessness she feels and the way spectators appear to sink into the ground when she soars off a ski jump — except maybe the feeling of pushing her physical limits during a cross-country ski race. The two sports have been a part of the 24-year-old New England native’s life since her grammar-school days — she picked up both at the age of 9 and in both, she excelled. By the time she...