Refer here:
http://wiki.project1999.com/Per-Level_Hunting_Guide
Plenty of good spots for all levels. I think at 12 I was in WC a bit just doing Kodiaks and Orcs. As soon as you hit 16 though, the Gnolls in EK are hardly ever camped, respawn quickly, and are all solo pulls. Just be aware of wandering wolves.