Only one or two visitors seems to have lulled your wife into a false sense of security. Most victims of violent crime are only victimized once but that one rape, mutilation, robbery or murder changes their world forever.
Don't let your wife think her age is a defense against being raped. We did a search of known rapists in a five mile radius of my mom's home a middle class suburb in Tacoma Wa. We found 200 known convicted rapists with a known preference for women 50 and older. Two hundred rapists within five miles unbelievable but true none the less and those where only the ones who preferred older women. Apparently your wifes and my moms age makes her a more vulnerable, an easier target not less desirable to the spineless cowards who prey on women to vent their rage.
Our home is much like yours miles away from the nearest town. Two miles up a dirt road with a 200 yard driveway through dense forest makes it invisible. The BG could chop us to bits finger by finger and no one would hear a sound, strip the house, kill us and burn it to the ground without anyone noticing. For that reason we have taken responsibility for our own security. With wireless cameras, motion and IR sensors. Secure doors and windows, three 100 plus lb Akitas and attack turkeys. NO trespass signs that assure any uninvited stranger the best they can hope for is to be looking down the wrong end of a barrel if they proceed uninvited choosing to be dealt with for what they are. Hostile invading trespassers.