The ideal location for first taking a horse outside is a long dirt road because it gives you plenty of room to move the horse forward and it gives him a straight line to follow. Beyond that, you need room to move the horse’s feet, meaning you can bend him down in circles to soften him, the ground is good enough for you to lope him, and there are natural obstacles around, such as trees or bushes, you can incorporate into your training.
The worst possible place to begin training a horse on the trail would be on a narrow path where you have no room to move the horse’s feet and you have to cross obstacles you haven’t introduced to your horse, such as a suspended bridge, water, steep hills, logs so high that he has to jump over them, etc. Putting a green horse in an environment like that is setting him up to fail and putting the two of you in a very dangerous situation.
“But, Clinton,” someone always says at this point, “that’s the only trail I have available to ride my horse on.” You have two choices: You either haul your horse to a suitable place to train him and build his confidence, or you buy a well-trained horse that will ride on a narrow trail and cross all of those obstacles. Horses do not train themselves. I cannot say that enough. Expecting an inexperienced horse to safely navigate a challenging trail is just setting him up to fail and putting the two of you in a very dangerous situation.
As your horse gets better trained on the trail, you’ll gradually increase the difficulty of the trails you take him on. Eventually, you’ll be able to ride on a 2-foot ledge next to the Grand Canyon with confidence. But it takes consistent training to get a horse to that point.