Great minds think alike. That south location would be my first pick too. Even though there are not a lot of trails, that spot monitors a whole lot of field edge. Just keep in mind the road and buildings to the east.

Get yourself a deer barrel for your 870. A smooth bore with rifle sights on it would be just the ticket. That is my personal set up. Ammo is cheap for smooth bores and you do not have long ranges on that property. If you cannot manage a deer barrel, at least get vent rib clamp on sights. I can shoot great at the range with a bird bead, the proverbial paper plate at 70 yards, but that accuracy disappears in the field. Open sights, like on a rifle, is the way to go for the relatively short range shots that you will have.

Bob