Finally back home (after this long road trip) and can give follow-on details.
Firstly, I am from Texas, as my name implies. (People from the US will know what that means) I know the deal, as well as what trespassing actually means. I took this encounter as either a threat or a warning that I was on private property. I was on a gravel road that maybe was maintained by the county or by the private citizens of the area - I can't say for sure, especially as an out-of-towner. The "trail" that I speak of was on said roads. That entire area could very well have been on what those residents would consider private property. I absolutely don't think that it was a warning about being near a hunt club. It was absolutely about trespass on private property, despite being parked on the side of the road.
I don't begrudge the residents of the area for asserting what they probably assume are their rights. My main concern is that the caches along the road in this area were improperly placed. Even if permission was obtained for those particular spots of land where those caches are placed, neighbors are still a concern.