The old saying goes 'the shortest distance between two points is a straight line". When riding the trail, it may be the shortest but not the best. Short-cutting across switchbacks in the trail should not be done. It creates a new tread, which is usually steep, causing erosion and gullies. Cutting switchbacks also constitutes abuse of our resource and the hoof prints that remain are a signature of who is to blame.
Many experienced horsemen tie a knot in split reins or otherwise fasten them together when in the backcountry. If a rain is dropped and stepped on, it could be broken, or your horse may act up. You may be using one hand for a pack horse lead rope, and your reining hand for dodging limbs occasionally. It you stop to adjust a pack, split reins must be secured or they will end up under the horse's feet. One way to secure them is to take a wrap around the horn and shove them through the latigo keeper slot.
Caution must always be used in handling the lead rope of the pack horse. Either carry it in your hand or take one wrap around the horn and place the end under your leg. The safest is to keep the rope in-hand. Never tie a lead rope to the saddle horn hard-and-fast! The lead rope should be changed from side to side or on the downhill side of the leading horse when traversing dangerous narrow trails. This will sometimes steer an anxious pack string or following horse to the danger side rather than push your saddle horse off the trail into trouble.
Regardless of what you see in the movies, never tie a horse by the reins. Always tie or lead with a lead rope which is either fastened to a halter under the bridle or passed under a bosal and tied around the horse's neck.
There are several good books listed in the appendix which cover more
details on packing, camping and trail riding techniques.