Hyannis and Provincetown are the heads and tails of Cape Cod. As the Cape’s de facto capital, Hyannis is the tidy town where everyone goes to shop, bank, visit the multiplex, or catch a flight or a ferry to the islands. By contrast, Provincetown is literally and figuratively “out there.” Built on sand dunes at the end of the earth, it is a place where anything is possible — and therefore inevitable. The two communities are among the most popular destinations on the Cape, and many vacationers like to sample them both. Here’s how they stack up on some essentials.