I'd counter that just because colleges care doesn't mean you should. Math in particular it's quite possible to pass a class without really understanding it. I'd wager that most students who took AP Calculus could not give a good definition of a limit. Indeed many math professors would much rather have students repeat calculus in college than blindly accept AP credit. Even if this allowed you to take more math classes, that wouldn't be much help if you don't know the fundamentals.

Also gap years don't have any impact on the level you come into college. If anything I came into college far more advanced in CS than my peers because of my gap year.