Thinly?
A trip to Broward or Palm Beach County would convince you otherwise. To say those are wall-to-wall Northeast liberal is only a mild exaggeration.
The real oldsters are packed into condos and apartments which makes them soooo easy to get to the polls to vote “D” every time. Just a sandwich and a list of preferred candidates is about all it takes. Or so I hear.
New England rats might dominate a small nearby state like New Hampshire, but so far as the state level is concerned, I believe they get largely absorbed. Sure, a county here and there will get overrun.