From recall in the graveyard, go twelve north, one west, up, one east (or one east, one up, one west), and two up. The mob is pretty easy, but all the bats will form on him, so it's suggested to kill those first. He's a low hp mob, with a very weak attack.
You still get boss credit at level sixty, and by then you should be able to attack the hunchback from the start, even with the bats forming on him, regardless of class.