Where can I buy accessories for horse riding in Manhattan NY?

" Those old cows knew trouble was coming before we did ." So begins the story of Lily Casey Smith, in Jeannette Wallss magnificent, true-life novel based on her no-nonsense, resourceful, hard working, and spectacularly compelling grandmother. By age six, Lily was helping her father break horses. At fifteen, she left home to teach in a frontier town -- riding five hundred miles on her pony, all alone, to get to her job. She learned to drive a car ("I loved cars even more than I loved horses. They didnt need to be fed if they werent working, and they didnt leave big piles of manure all over the place") and fly a plane, and, with her husband, ran a vast ranch in Arizona. She raised two children, one of whom is Jeannettes memorable mother, Rosemary Smith Walls, unforgettably portrayed in The Glass Castle .