To defeating the Wayfare Inn Boss, make sure you have a ranged weapon. First, take out the underlings. Do not hit the Boss; he will not attack you until you attack him. Once all the Goblin underlings are dead, you can attack Harnak. When he starts to chase you, run towards the tables on the right. Jump to get over them. Once on the top side of the tables, line up on the corner closest to the fireplace. This should get Harnak stuck by the bottom table, leaving you free to hit him with your ranged weapon.