Watch the Travis Train online guitar lesson by Joe Dalton from 50 Acoustic Blues Licks You MUST Know
This lick opens with an embellishment to the E7 chord. The embellishment is actually adding an A chord. The walk up chords are the harmonization of the bass line E, F#, chromatic passing note G, G#, to the A chord. These chords are E7, F#m7, Gdim7, E/G#, then we are on the A7.
If you have never Travis picked before, you will need to spend some time on just the thumb pattern in the right hand on the A7 chord.