(Leisure section) DIAMOND IN THE ROUGH by Dave DeWitte of The Southern Illinoisan [clip]...Don Combs, Jr is purty sure his daddy would like the way he's running the ranch. .....The ranch, adjacent to the trail of Tears State Park on Illinois 127 in Union County, became an immediate hit with horseback riders when it was opened two years ago by Combs and his father, Don Sr. It's become an odd kind of success story, in an unlikely way. ....The ranch lost its founder on July 4, when Don Sr. died of