I've recently hit 42 on my TH, and I'm abit unawares of where to go. I'm after a place that preferably hasnt got many (or any at all) aggro mobs because I'm also leveling a wolf, and mobs that drop herbs.
I did 40-42 in sea of spores, but theres alot of bots there so its abit too contested.
(just north of i Ivory tower. Between the tower and the fort)
fomor, fomor elder, bubears and bugbear warriors and high warriors.
Grab coins of magic quest in Hunters Village before doing Ivory Tower area and u will collect some coins as well while levelling there. Generous pot drops.