Yes, I'd think that the family group/clan is a characteristic of these things. As you said, reports of BF are almost nation-wide - meaning - they too come from a significant breeding population. The size of the clan that we shared that mountain with numbered at least seven - as that's how many pairs of eyes we lit up the night they came for the deer they'd badly hurt, and we'd shot to put it out of its misery. But we'd only spot one at a time during light hours, on four occasions.
I'd suggest that in areas in the east, for example - they may not have the more defined valleys, but a lot of eastern areas have something else. Game AND agriculture. Lots of game, and lots of agriculture. They have dense hollows, lots of areas defined by creeks, lakes, and rivers. I have no idea as to the size of a group's territory - but I'd assume it would match the population/game/agriculture available. They're not stupid - rather - pretty clever.
My point is this - these things if not dumb animals - and what I believe to be some primitive relict species of some kind of caveman - are highly adaptable to their environment. They don't need what we would consider necessities. And I'd venture to suggest that whitetail deer are everywhere! Hogs are heavy in many areas of the Eastern US, low and high.
Plentiful food in southern and eastern swamps - plenty of corn and soybeans in the midwest - plenty of wildlife and seafood in the salt marshes of the eastern US.
You can take any Cajun - show him a ditch - and he'll come up with lunch. And as good as Cajuns are - these things are Master Scroungers.
Oh. And they DO use rocks as tools of a sort. They can throw double-fist sized rocks with great accuracy. Small ones too.