Ideally you'd be using an already trained trail dog to teach the new one. Bummer. Most trails require that your dog is on a leash anyway, so you might as well get that part of the training mastered. Until you know how your dog will react to other dogs and/or people on the trail, you should have it under leash control. The last thing you want to do is wander aimlessly searching for an untrained dog who took off after (you hope) a deer. You also don't want your dog to make a turn you didn't or vice versa. I've had both of those things happen and it's gut-wrenching, exhausting, and your fault. Once the dog is comfortable on the leash in the woods you can start using increasingly long lengths of rope until you feel like your dog is going to be there when you look up from taking a leak. By the way, don't bother hanging on to the leash/rope. You've got enough to worry about navigating in the woods. Use the hip belt on your pack to secure yourself to Fido. It makes EVERYTHING easier!!!