All poets do. Products of the imagination. And thank god for that. I imagine that's why we find it capable of catching so much. Anyone can dictate the mundane moments of their day to day life.
Artists shape the raw material of their lives into something more.
Abbey was an artist. A novelist at heart. I think we need to look at Solitaire as a piece of literature, and not necessarily as a biographical document. Obviously, it's not a novel. Abbey had enough sense, as any artist should, to break rules and regulations in pursuit of the appropriate structure and form for his work.