I killed him at Lvl 15 (Thurgist) by going around to the open side of the house where you can see him standing inside. Since all the surrounding goblins protect each other when attacked, my best strategy was to just target him when the majority of the wandering goblins were away from him, sic as many pets on him as I could for a quick kill, then start running for the Mine entrance (a big pile of rocks on the wall, south (?) end of the house). By the time I got to the opening of the mine, Grilk was dead and the quest piece appeared in my inventory , then I zoned into the mine. Sustained minimal damage (12 pts).
Britnee