I've done a lot of NATRC. They have been around for years. You will have to check and see if they hold regular rides in your area. They have a strong following in some areas and no presence in other areas.
If they hold rides in your area. They are a great group to particpate with. Everybody is very helpful. They will help you find a mentor for your first few rides to get you comfortable with the sport. It's a great sport to further your knowldge of horses and get you out to enjoy a new trail.