In hot weather, it s a good idea to freeze one bottle of water. Power Gel, salt, snack food. Duct tape, Compeed band-aids, tissue, baggie, ginger, Advil, Tylenol, Tums, candy. You will be running in wilderness. Be prepared to encounter heat, altitude, streams, rocks, rattlesnakes, poison oak, and possibly mountain lions.
Falls are a distinct probability.
Many reasons to not be alone on the trail. Wear hats, visors, bandannas, sleeves, and sun block. Do not wear headphones. You will not hear rattlesnake warnings, approaching mountain bikes, or lost runners calling in distress. There are no toilets on the trails.