The dumbass should have left the property when asked and not ignored the no trespassing signs. I might have reacted differently but I also don't live out in the middle of no where. Eliminating the threat is all that matters, so +1 to OPs wife for keeping her family safe. Keep on being safe.
You were being cased.
If he had truly wanted directions, he would have flashed his lights while on the road. Never show them where you live if you're being followed.
You ignored the "I don't really know or care all that much." I wasn't asking a question I expected an answer to, it was rhetorical. We live a long way off the road, we have excellent security, and at least one armed and determined person is around almost always. Short of a determined invasion we're pretty safe around here.
I get people asking for directions all the time when I am out on my daily bike ride out here, we are a long and confusing ways away from anywhere and I am ALWAYS on my guard, but I also give directions.