Update.
Snowdon Tourist path; two and a half hours to do the five miles to the summit. Probably 30-40% rideable. It seems steepest around the Clogwyn station which is about 3/4 of the way up.
The ranger descent is great, fast. Loose, sometimes deep shale.
The descent gets steeper, rockier and more techinical on the shoulder of cloggy. Very rideable, though there are about four drops you might want to step round.
The extra push to the top of the telegraph route is worth it. The connecting trail is sign posted, but very indistinct. The telegraph route is a blast, all the better if you can bunny hop the drainage channels.
More grins than a rather large grin factory.