I can't see season 3 happening after the comic got canned. Greg talked about a 40 year time jump if the show got renewed. Not sure how that would sell to studio execs.
It'd be kind of funny if season 3 did happen, with the 40 year time jump. On one hand, people would be overjoyed by a third season. On the other hand, those same people would be bitching up a storm due to the time jump.