Starting a riding club is a great idea. A friend and I started a County chapter of the Ohio Horseman's Council years ago. They are an affiliation, of The American Horse Council. It was always a good time, riding and having cookouts. Here is a link to the
Horseman's Corral publication. Most of the clubs are in Ohio, but a lot of them post their newsletters and minutes of meetings to give you an in-site. You will have to register to read online, but it is free. Good Luck!