Mike and I worked it out on Monday.
1. Start with the open G chord position, your finger on the low G on the low E string, that's your first base run note. 2. Then you go up to the A string, 2nd fret and play the B. 3. Then you play the 5th fret on the A string for a D note or you can play the open D string.
4. Next you play a E note on the 2nd fret on the D string.
5. End the walk up with a G on the 5th fret of the D string.
6. Then walk it back down with an EDABG.
7. So the bass progression walks up GBDEG and down EDBG
8. An alternative is finish the walk up with an F then down.
9. You can either play the D and G up on the 5th fret or on the open D and G strings but you can use this same progression all the way up the neck and use the exact same finger progression up one string starting on the C for the C bass run and then move that up 2 frets to start on the D for a D bass run and only have the one set of fingerings to learn.