Look into some security cameras with infrared lights, dvr, motion detection, and maybe a trail camera.
This is more in line with the type of answers I was hoping to receive. In fact, I've been considering cameras, IR detectors, remote sensing devices, trip wires connected to an alarm, or anything else which might be an effective aid in allowing me to know if someone is present without my knowledge with the added benefit of possibly even helping the police to catch them. Assuming that the police ever bother to respond to my call.
At this point, setting up an effective perimeter defense line is my primary concern, so all suggestions which help me to achieve that specific goal will be greatly appreciated.