The direct answer is, "No, nobody knows the first route." But some of the early (i.e. 1960s) routes included Sunset Slab and Mescalito - Original Route. Few people would be as qualified as Joe Herbst to speculate on this, and though he had done much prior, he has expressed the opinion that the first real route was Sentimental Journey.
That's interesting Larry, thanks... I'm really curious about Williamson and his crew... seems like there's a lot of history on Joe Herbst's adventures but Williamson putting up the Fox so early on seems really mysterious and impressive! (as are all of the Herbst routes:)