Alright guys, i'm going to try to get a helpfull guide on this website,
When i was leveling my mage, i found an alternative spot for the Guild achievement: Critter kill squad.
The location is in the eastern plaguelands when you enter from WPL and go to the bridge go north to the cave, there are tons of Critter beetle's cockroache's spider's and scorpion's there.
I am unsure howmany kill you can get a hour, but its good ( prolly not as good as the isle's in northrent, but its an alternative for the lower levels in here i guess.
Here is a screenshot of the location :
and a screenie of the ammount of critters inside:
The downside, for lower levels, is that there are some nerubs around, but there not too much to handle if your around the leveling range of EPL.
Ps the cave is longer than it looks on the screenshot.
I hope this helps.