Just about any town in rural America. PA, MN, OH, NY all have these towns where you can just walk into anyone's house without a problem.
I can't speak for PA, MN, or NY, but I grew up in small rural towns in Ohio. I can assure you that people certainly *did* lock their doors and that crime, while not *insanely* rampant, was far from rare. I am, however, told that people were less likely to lock their doors when my father was a kid.
I knew a number of people whose homes were broken into while I was growing up and the thefts have only gotten worse in the last year or two as crime rates have risen due to the poor economy.
Add to this the fact that there is a prevailing sentiment in a lot of the smaller rural communities here that the entire world should be Christian (and they are willing to trample the civil rights of others to that end), that anyone less conservative than W is causing the ruin of this country, that all Muslims are evil and want to destroy America (I kid you not. Actual comments from the local paper), and, frankly, that if you're not a white, "God fearing", good ol' boy that you should just get out.
Sadly, I'm not kidding and I'm not exaggerating. I will readily admit that there are many good people in this area, but there are also a very large number of people who display the behaviors and prejudices that I have listed above (as well as more than a few others). It's enough to give you a headache purely from trying to not scream in frustration.
Don't try to idolize the small towns as bastions of everything good in the country, because it's just not true.