Your generalizations are absolutely correct. I speak from personal experience, as I live in Chicago. I guess you could say I live "downtown", if you could call it that, as it's basically a patch of hard-packed dirt that serves as a "town square" of sorts surrounded by the burnt-out & partially-collapsed shells of once-permanent structures intermingled with crude huts and flimsy market stands.
Our dialect here is a mangled, barely-literate system of monosyllabic grunts that is only vaguely recognizable as having once derived from English.
When we're not engaging in menial labor in deplorable slaughterhouses and rock quarries, we venture out of our rudimentary shelters to beat up minorities, wager our food stamps on cockfights, drink copious amounts of homemade liquor, and, when there are no minorities left to beat up, drunkenly brawl with each other.
On Sundays we all attend Latin mass. At least I think it's Latin...it could be English for all I know (we speak a primarily grunt-based dialect, if you'll recall).
In summary, everything between the coasts is just awful. We are a godforsaken group of sloping-browed heathens who will quite literally eat you alive if you attempt to venture near any of our Mad Max-like settlements. I would advise you and all like-minded coastal urbanites to stay in your cities and not attempt to make any contact with us, for your own safety of course.