Use IR beams to detection breach of the perimeter. Have them turn lights on. Back this up with motion detection lights. You can have the beams also trigger an audio message that will play through some speakers. Your recorded message will announce something to the effect of: You are not authorized to be here. Your presence has been detected and is being recorded. The authorities have been alerted and are en route to this location (repeat). Feel free to insert the audio of a screaming little girl as this will save you the embarrassment of doing it yourself.
Use IP based day/night megapixel color cameras with motion detection to record all areas, not just sensitive areas. I recommend at least 30 days of storage at 7 fps (no less) per camera. Record to a DVR that is secured and hidden. Off premise recording exists but is pricey. DVR should support off site access and control.
Signs should be mounted around the perimeter and be VERY visible. They should address all unacceptable behavior and announce the video surveillance.
Your intrusion detection (burglar alarm) will support the IR beam detectors. Use motion detectors and contacts where needed. Be sure that you install a discreet "hold-up" button(s) of some sort near sensitive areas. All intrusion activity should be recorded for reporting by your monitoring agency (ADT). Also, ADT does not have a specific office here but you may want to call them anyway.