Oh, don't worry, I've been hanging out in real-person fandoms for 5+ years; I know all about crazy premises, too -- the crackier the better, basically. RPF is pretty much funnest club ever.

in which every other story contained a ridiculous crossover or a zombie apocalypse or one of the characters turning into a car

Were you in the AI fandom? My word, the things fangirls have made Adam Lambert do and endure in fanfic...