grobb isnt bad for a necro. the mobs are a little more difficult but the zone modifier is much higher then other zones, as well as necro class quests. also Mielech a is nearby. you get to hang out with trolls, which is cool.
North newport is popular and there is a necro guild with quests including the best gate
in the game, which I carry every where always. NNP xp kind of blows but its easy. sewer xp is much better but harder. you get to hang out with humans and wood elves, which is not that cool. but we did import some trolls as a fashion statement into the sewers
ask in guild where good spots are after starting zones.