While you are correct that a person could get from the campground to the Morphew house, the campground is not on the same access road as the Morphew house. There is a two-track trail that goes from the campground and intersects Puma Path just south of the Morphew house, but it is not a main traveled way. Probably used by hikers, trail bikers, four-wheelers, etc., if there is legal access to do so. (Might be an agreement between the campground and the subdivision to allow access to County Road 225 from the campground without going out on Hwy 50.)
I, too, would have a camera and a gate, or at least a motion detector that would alert the house to a vehicle coming up the driveway.