Portydave: The only info I have about Caderg are posts from the late Messiah (used to post on STW). He described Caderg as almost unridable (+ I gather he was a pretty competent rider).
The route incorporating this I fancy this summer, is to start at Fergus in Glen Isla, ride up via Craig-lair, Bawhelps (don’t need any help with mine, thanks!) to Mayar and a decent of the Kilbo Path to Clova. Glen Clova, Bachnagairn, Broad Cairn, Carn Bannoch to ride the awesome Carn an t-Sagairt Mor track down to Loch Callater. Up the landytrack to Cairn of Claise to reach the path that circles the boggy plateau via Druim Mor to the top of Caderg.
A shorter variant would leave out Mayar, do Finalty Hill, Tom Buidhe then Cairn of Claise.
I can see myself getting to the edge of Caderg, turning tail and riding down Monega Hill instead!
All the blank bits on the map in this part of the ‘Gorms have tracks (sometimes tiny); all you need are good visibility and a dry spell to ride up there.
Similar ilk perhaps to the Dumyat route is the descent of West Lomond Hill down to the Bonnet Stane; via the straightline path used by fell runners, not the one further NE traversing the fence. Don’t know if it’s been ridden; looks well steep!