[Blue Jays]

Excellent point, Blueflag.
I have contemplated distances...rifle, shotgun, pistol, etc.
Another thing is simply having the information that mobs that don't mean well are potentially en route.

There are countless websites dedicated to the topic of reasonable preparedness and all. One would seemingly have to align himself/herself with likeminded people in the same neighborhood. After all, one cannot do it alone. A person eventually needs to drink, eat, and sleep. Your concept of thinking of defensive perimeter in depth is a good one.

[Blueflag]

308
223
22
12
45

Plus the right optics and lights

Plus the right plan ;-)