AllDodge, if you want a hard wired system, but don't want false alarms via deer, dogs or whatever, the only way I can see that working is with multiple sensor setups. A single sensor will trigger if anything passes it. But you should be able to get one that takes more then one sensor to trigger. And have them set apart so a deer or any type animal can't possible trigger two separated triggers at the same time, but a vehicle still will. And most any hardwired system can lengthen the wires without any problems.
Of course anything can be falsely triggered. If two or more deer are coming across the two separated sensors at the same time, it will still go off. But that is a remote possibility.
One thing you really don't want is an RF transmitted setup. I installed a simple backup camera in my wife's car some years ago. And the power was only on when in reverse for the camera section mounted on the rear tag. But the monitor was on any time the vehicle was on. I was amazed at the video I was receiving from other homes, shops, businesses as you would drive down the streets. I even had videos of business safes inside the businesses even when they were closed. Now that is not a good thing at all. People don't know that they are transmitting the inside of their homes to everybody with RF systems. :nono: