If you were walking north and not along the river, that is in the range of Mount and Jemima Mount. Mount has no rise but I remember hiking on the back side (west) of Jemima Mount and seeing fence posts and old wire. That sounds like a good area to explore and I think I will do it in cooler weather.
The question in my mind is why not just drive there if that is where they took him. He said one of them was not in great shape. I would think the location they wanted him to see was not near a road. Unless, they did not have a vehicle good enough to get there. Back then the roads were not as good as today.
Guy