I agree. I'm unfamiliar with the USGS Lidar survey, but the image does appear to have low elevation south of the note's location, as you say.

As for the trail network, it exists—I've surveyed it myself. The trails have no signage, but they are not gated or fenced off either. It is quite unclear how to characterize them. The network appears to be in various stages of disuse They are connected to the Searcy Bike and Walking Trail.