Smith Valley has glorious fields of alfalfa, robust cattle, and a very high regard for horsemanship. Today this art is being celebrated in a covered arena that would easily accommodate the Goodyear Blimp. Banners flutter, music blares and Donna, Queen of Camelot, rides serenely into the arena. Dusty and Donna Hustace are owners of Horsemanship Headquarters, which holds a horse camp every summer."Once upon a time, long, long ago, in a far off land," and so the pageantry unfolds. Emily, Cassidy, Rebecca, Heather and Marsia, saunter into the arena. Each is wearing a flowing gown that falls gracefully over the …