In reply to Beano:
There is a good loop starting in Alwinton, climbs up along Clennel Street heading west, then over Windy gyle on the border ridge, to a superfast adrenaline inducing drop down a spur to a single track road in the Coquet valley, either stay on this or follow the BW over the Peth back to Alwinton (you can also add on the uswayburn, short lived but one of the the best bits of scenic singletrack in the heart of the Cheviots).
Post edited at 20:57