Lower Guk is the place to be for undead once you get past the live bats on dead side its all dead mobs except for hand named (even undead names see invis so dont charge into a new room with out checking for em)so you can move at will with ivu.
Cleric can use pacify to single pull rooms wizard can evac if pulls goes bad. Mobs gradualy increase in level as you work your way deeper highest level area is decent exp until around level 53 you can stay longer but exp rate slows down.
Edited, Tue Oct 4 22:58:25 2005 by SiddarA