How much of the books do you think they read? We know Dean read Route 666, but how far do you think they got in the series? Because...did Sam ever tell Dean about the 6 months he spent alone in Mystery Spot?
I only assume they didn't read the whole thing. Because you think some of those secrets would be worth mentioning....
I must say, the potential for fic from this episode is so astounding, that I believe it may just be better to leave it be. (Yes, that is how my mind works).