In reply to Ollie B:
Bear in mind that times quoted for the 3000s are often summit-to-summit, rather than road-to-road. That includes Colin Donnelly's record (4:19 as mentioned above).
The record route starts from the top of Snowdon but it's actually a more natural line to take Crib Goch first from Pen-y-Pass... slightly slower summit-to-summit but quicker overall.
Anyway, I did it last Saturday in 9:50 from Pen-y-Pass to the Aber carpark, and I'm a pretty average runner, so 10 hours is probably a decent benchmark in good conditions.
> the BG is 66miles and can be walked in under 24 hrs.
> only once I think!
...by Billy Bland, who also holds the all-time speed record, over an hour faster than anyone else...