The sign is a simple white sign with red letters that reads "Bogg In".
The name of the road off 77 is Mobile Swamp Rd.
Type "Mobile Swamp Rd, Chipley, FL" in Google Maps and it'll take you there. Mapquest also shows it. Yahoo maps doesn't list Mobile Swamp Rd at all. Looks like it's south of the golf course, though.
While searching I saw several places that looked like they needed exploring.
Anyone know what this is in the pic? Looks like some kind of BMX or motocross track. It's right below Sunny Hills.