Drop the car at Achnashellach, down to Coulags up to Bealach Ban, round into Coir Lair and back to Achnashellach.The last section is some of the best rock riding in the higlands,like Laggan without signposts.Pretty much rode yourself into the ground covering the three routes mentioned above.And x3 the Liathach route.I wouldnt bother because the hill south of it offer so much more riding anyway.
As for walking in the area take your pick, but a circuit of Beinn Dearg could involve a cycle into the bridge about 1.2 miles in, hide the bike,and then pick it up and enjoy the best of the Lithach path without the hike a bike bit further on.
And if you want a really scary descent,head for the Bealach na Ba at Applecross.Just don’t make any mistakes,they don’t call it terminal velocity for nothing.