Quickly...
-The Bow is visible on several decks on the ship....
-The Haven offers a premium cruising experience in service, food, cabin and convenience. It costs more because everything from the Restaurant to the Butlers to the Concierges are at your service.
-Paying for the Haven is a choice, not a necessity on the ship. You can still enjoy MDRs, Buffets, free entertainment, bars...all over the ship without being in the Haven.