Go by your local feed stores, the farm type ones as well as chain ones, check out bulletin boards and at the REAL farm stores...the ones that farmers use, ask them who around there has horses and who boards.
Go down all the roads you can find and stop at places that have horses.
Go to tack stores, and to trailer places and stop and tack to them.
Get phone book and call every single place that either breeds, trains or boards horses.
Just get out there and beat the pavement.
When I was moving 1000 miles north, I got a phone book up here while looking at houses in every town I was looking in...decided on house, and when got back to AL, called someone listed under horses, left message, turned out he was mayor or town, he called me, told me about someone that he would go talk to, and see if they wanted to board?
Voila! Had that figured out in less than one day. And from 1000 miles away.
You are right there, this will be a cinch.
Horses make me a better person.