sounds like the wild, wild west. Take the law into your own hands. Hide on the course, wait for 'em.
What's it going to take, somebody getting murdered for the sherriff to remember there's a town there in their jurisdiction?
A more 'serious' idea might be to send the county sherriff (that's elected, I assume) a nice little letter/petition signed by community members (not just disc golfers) dissatisfied with the level of protection and response times, and then illustrate your willingness to ensure he's not re-elected if it doesn't change. Include pictures of the park's damage, if you have any. Then, CC the governor, or the county magistrate, or whoever is the sherriff's superior.