I did this last year and the route most people took was:
Back road from Gala to join A7 (just follow everyone else
).
A7 thro Selkirk to Hawick
B6399 Hawick to Newcastleton
Newcastleton to Langholm by unclassified road that climbs from the Post Office then A7
B7068 Langholm to Lockerbie
B7076 (old A74) Lockerbie to Moffat
A708 from Moffat to Gordon Arms. Turn left to climb Paddock Slack (B709) to Innerleithen.
From Innerleithen you can either take the main road A72 back to Gala or take the far quieter road to the south of the Tweed and follow the NCR1 signs to come back into Gala the back way
I've PM'd you some info
