I have never done this walk, but from a motivational point of view I cannot imagine that Fort William is a more attractive destination than Cape Wrath
I love Cape Wrath, it's one of the places I keep on talking about to long-suffering friends and colleagues. I can't imagine a better end to a long walk, whereas Fort William..... nah, it's just a town - you want to leave all that behind, not walk inexorably towards it.