VAIL — With the slow start to winter, resorts are aching. Resort operators and community groups are hosting free dinners for idle workers and blasting grassy slopes with man-made snow. But while ski resorts bemoan Mother Nature’s dawdling, not all mountain businesses are dragging. Visitors still go looking for thrills when the dirt-flanked ribbon of artificial snow gets old. “And we are ready to greet these folks with open arms and red carpets.