"Pop" for soda is a Midwest/Plains states thing, not Northeast.
Make sure your MC packs a
real winter coat. My aunt from Tennessee showed up here at Christmas time with a, well, windbreaker.
Seconding the iced tea thing: In the South, iced tea means sweet. Up north, unsweetened. Unless it says "sweet tea". Can't speak for other parts of the country, though, but I suspect that everywhere besides the South iced tea comes unsweetened.
Life in the Northeast is generally "faster" - people walk faster, people have a more rushed demeanor: gotta get to work, gotta get this done. One could make this comparison with East Coast vs West Coast, too. Doesn't mean you
actually have somewhere to go - it just seems like it, in comparison.
Southern hospitality - when it's present - is a real thing. That does not mean we Northerners are rude. We're just in a hurry.
But as long the MC packs warm winter clothes s/he'll be fine. It's not a different country, after all. We all speak American.
Oh, if the MC is church-going, s/he may remark upon
not seeing a church every 100 feet, like in the Bible belt.
(Spoken as a Southerner/Northerner)