I Want to Learn More About Endurance/Trail

I would really like to learn more/get involved in the sport of endurance or competitive trail. I have a lot to learn but I'm not sure where to start. I don't have many friends who are involved with horses and none of them really know anything about endurance.

So I live in BC, Canada and I am just wondering how I could get involved and learn more about these sports. Also, if anyone has any suggestions for riding excercises I could do to learn how to be a better endurance/trail rider that would be great.

Please bear in mind that I only half-lease an older horse so I don't want to put her through any stressful excercises, I'm more interested in learning how to be a better rider.