Aye, the Duke's Pass was really pleasant. I had looked at the offroad alternatives, but there was hardly any other traffic (excepting deer), so it didn't seem worth it.
The track up from Killin had at least one gate, from memory. But mostly I remember being really frustrated at having to brake for the narrow chicanes and curves and lose all that momentum.
ISTR making a comment about blowing games and soldiers, giving up on the daft forest roads, and riding the Duke's Pass, and I agree it is most pleasant. The viaduct photos bring back some very happy memories. And what a grand time you had of it. Smashing ride report Deano.
ETA: Union suspension bridge - WIN. Love it. Also, cycling over the causeway to Lindisfarne, definitely need to tick that box Deano, preferably with a stonking tailwind