first of all this is my opinion and there is a good bit of evidince but im still only in the middle of my second reading and my notes are no where near complete.
i think A}johnny is obviously crazy B}he wrote the entirity of the book (with the execption of some of the appendixes)
1} the first thing j does within the body of the book is tell you the story about how while at a bar with lude he told the girls the "pit boxer" story, hence you know he A]tells storys well and B}has no qualms about using this skill subverively (also note the vaugely exotic sorta south american captain of the barge in the story z's ethnic background is equally ambigous and also vaugely latin american)
2) the first chapter of zampano's writing is essentialy asking whether the navidson record true varite or a fraud, hence the core question of the book has already been handed to you
3) the words of johnny himself P.20"we all create stories to protect ourselves"
thats all i have for now this is my first post but im write more as i find new info