The intro to Tennessee Line has more than one guitar playing, but this is the 
distinctive melodic part played by the lead acoustic guitar.

Capo 6, then make an easy variation of the C chord:

Cadd9
|3|
|3|
|0|
|2|
|3|
|0|

Finger pick this:

|--------------------------------------------|
|------------3---------------------3/5/3-0---|
|------0-----------0---------0-------------0-|
|--2---------------------2-------------------|
|3---3-----3-----3-----3---3-----3-----------|
|--------------------------------------------|

Pay special attention to the rhythm in the song and that should get you started.