Deer and antelope still play near the Casper KOA. More than 75 percent of the world's pronghorn antelope live within a 90-mile radius of Wyoming's second-largest city.  In many places, the Plains look unchanged from the days when the Oregon, California, Mormon, Bridger, Bozeman and Pony Express trails converged here along the North Platte River.  Trail ruts are still visible.  Visit the National Historic Trails Interpretive Center or browse pioneer exhibits at the Fort Caspar Museum and Historic Site.  Public tennis courts are located across the street, and golfers can choose from two public courses, one of which was designed by Robert Trent Jones, Jr.  Or just relax in the big covered pool and hot tub at the Casper KOA (Memorial Day to Labor Day). The whole family can make itself at home here with mini golf, banana-bike rentals, a playground and a pet walk.