We did the route in Kenny Wilsons book and its one of the best if not the best I've done. Its a long day out but is mostly rideable, although the first climb needs a bit of pushing and or carrying. We stayed at Lochcarron and cycled to Coulags from there which is a nice easy warm up. The descent to Annat and the one to Achnashellach are incredible.
The photos don't do it justice really. There is another loop starting at Torridon which is the most southerly point and goes in a clockwise direction. Its also on the book. Shorter but a lot of carrying.