I read the Calculus Trap article recently, too, and I thought it had a great idea. I'd look to fill the math gap with wonderful chunks of discrete mathematics learning. Probability, number theory, graph theory, predicate logic, etc. and all the accompanying cool puzzles that go with them. I think that under-served area makes future math even more interesting along with providing parallel tools to self-enrich.
(p.s. I abandoned the Calculus route in college and had a math minor with just discrete mathematics classes)
