Watch the Cumberland Gap: 1 online guitar lesson by TrueFire from Americana Greatest Hits
Lesson Source: Cathy Fink's Clawhammer Banjo: Intermediate
There are more versions of Cumberland Gap than I'll ever know, and in more tunings.
I first learned this from David Holt in 1978, but I'm sure by now I've put my own twists on it.
Cumberland Gap tuning is used here (though there are many other tunings it can be played in).