Interestingly, Woodard's book echoes an earlier work, Joel Garreau's 1981 The Nine Nations of North America (https://www.amazon.com/Nine-Nations-North-America/dp/0380578...). Garreau, however, put all of NC inside his "Dixie" nation, the analogue to Woodard's "Deep South." I wonder how much of this can be chalked up to differences in methodology, and how much to demographic shifts in the three decades separating Woodard's work from Garreau's.
For what it's worth, my own experience says that the area for "Greater Appalachia" is pretty much 100% correct. The borders aren't quite sharp, and interesting things definitely happen where two or more "nations" meet.
I also know that West Virginia and middle Tennessee feel like "home" to me, and I'm from the Arkansas Ozarks.
pin, pen, pan
all sounding a bit like "pe~an"
https://english.chass.ncsu.edu/faculty_staff/wolfram https://linguistics.chass.ncsu.edu/thinkanddo/dialecteducati... https://linguistics.chass.ncsu.edu/thinkanddo/vonc.php#video... https://www.ncfieldfamily.org/nc-living/different-dialects-n... https://languageandlife.org/ https://ocracokepreservation.org/
Also the pen/pin thing sounding the same is definitely a thing.
But that's similar to what I experienced in Seattle, except they say "y'all" too to be gender-inclusive now. You can spot a WA state accent by the way the say "bag" though (sounds like "beg"). My favorite give-aways for southern without accent though is saying "might could".
The infamous "northwest vowel shift"! I do this too (grew up in the suburbs of Portland) and it's common from Oregon up into BC. Didn't realize it was different until I moved to the midwest for undergrad.
I did have a hard time in the Deep South, especially the way they would say things like ve-hi-cle and such.
My question for you, is do you notice it when eastern WA people say it? Does it stand out to your ear? If not it's possible that you're just used to hearing it either way and not attuned to the difference. I'm like that when people say "pen" and "pin" differently, I can't hear a difference at all. But the "bag" thing stands out a lot since it's different to me.
Also, we said "Coke" for any type of soda. For example, you would say, "Do you want a Coke?" and someone would say "What do you have?" and we would answer "Pepsi, RC Cola, Dr. Pepper..."
My family has been in NC for generations and my father's side of the family refers to any soft drink as a co-cola. Every soft drink is a co-cola.
Also, my grandfather always used to purposefully mispronounce Ocracoke as O-row-key-coke. Everytime I see Ocracoke I instinctively pronounce it in my grandfather's manner.
One thing I noticed from looking at the data for the accent quiz, is that North Carolinians are far more likely to NOT say soda/pop/coke in actual conversation. We just use "drink" for everything. I attribute that to the fact that sweet tea still seems to be the most popular beverage. It was the only place on the map where I saw that particular quirk.