So, uh... Do you just plan on watching them on tape after they fuck up your grass? How are you expecting to either identify the subjects, or be alerted to their presence? Then, avoid false alarms if you intend to go with a motion activated audio alarm?
I'd go DVR card connected to a computer. I'd use fixed bullet cameras on specific areas. I don't know your property, but if you know of a place someone will go through your yard, I'd focus a narrow view camera on that so you can get a facial shot.
Do you believe the subjects will arrive by car? If so, I'd have a camera placed to get a decent description of the vehicle.
I'd make it very obvious that you have video surveillance equipment. That should deter most people, expecially simply vandal based crimes.
Motion detector lights can be used, but many cameras will white out if too much light is used.
-Steve