PBS has a very good documentary, "The Appalachians," which explains the history of the region, the people who settled there, etc. You're correct that a lot of settlers came from Scottish backgrounds. My mother tells a story about being at a dinner party in New York in the 1960's (she lived in Spanish Harlem for a year, which had to have been a huge change for a girl from the mountains) and asking someone to "reach" her a dish. A Scottish woman who was there told her she hadn't heard anyone say that since she left Scotland.
Also, notice bluegrass or old-time music, and clogging or flatfooting -- how much they have in common with Irish and Scottish music and dancing.