Trail riding is one of the most enjoyable things anyone can do with a horse. I firmly believe that every horse benefits from being ridden on trails, in open spaces, through forests, up & down hills, and just basically anywhere outside an arena. Ideally, I'd love to trail ride every day, and do arena work two or three days a week.
If you enjoy trail riding, want to meet new friends who trail ride, and think you might want to compete, but don't really have the time or inclination to get into condition for 100-mile endurance rides, you may want to check out ACTHA. The American Competitive Trail Horse Association sponsors hundreds of one-day events all across America. Chances are, there is one near you. The membership fees and entry fees are not too outrageous, and some nice prizes are awarded to the top scoring riders, as well as annual high point awards in each region and nationally. Divisions include Open, Pleasure, Junior, and Buddy (which is not scored, just ridden for fun & experience). Any horse of any breed is eligible to enter, registered or not. Riders follow a 6 mile trail, with 6 natural obstacles scattered throughout. Each horse & rider team is judged on how they negotiate each obstacle. It's fun, and a great learning experience.