Anyone know anything about this old route in Northumbria/Cheviots...?

From what I can gather, it appears to be a 100 mile horse-riding route which may (or may not) go up and down the Cheviots on both the English and Scottish side.

Also appears to be linked with the old Roman "Clennell Street", but whether they share the same route along their entirety i'm not sure.

However both the Border Ride and the Roman street are only intermittently marked on the OS Maps.

Anyone have more detailed info/route? Or any suggestions where more info could be gained? I thought about contacting local horse riding clubs, but most of them appear to be geared up to tourists...