Evan King's house is the largest of the four homes in Arefu. In order to enter the house, you have to pick the (average) lock. You will not lose Karma if you pick the lock, but Evan King may attack you if you enter while he's inside.
It is a small two-level home. The second floor houses some ammunition boxes, some metal boxes, and other random loot. It is set up much like a typical Megaton two-level building, with the main room being two stories high due to a balcony.