IF someone steps up here were my thoughts on how I was going to approach it.
OK Background:
Here is the EQaltas link to Grim
http://eqatlas.com/luclin/grimlingforestmap.html
If you look at the map you will see the northern most 2 camps.
Item labeled #1 is the town and is very populated.
Directly below that is a camp with some higher end spawns (not too much higher end)h
All the camps (with the exception of the town) have a set number of spawns, usually not more than 12 at a time. While they are very aggressive and seem to have a decent sized aggro range. Harmony DOES work here you just have to be careful of the wanderers which is why it would be a good idea to set up camp on the east hillside. This will help avoid most wanderers.
The guards at the outpost will help with the Grims, and I believe they helped with the ocassional sonic dogs I ran afoul of.
I have had Nealyn up there and cleaned out the whole north camp (not town) using harmony and snare to pull the closest ones first and working my way back in further.
This is what MY plan was.
1. Move out from the port in area in the putpost, (#3/#4 on the map where the BANK is), head just north of the outpost and set up on the wall between the camp (#2) and the outpost. From there clear the path in of wanderers and use harmony and single pull grims out. Adjusting as needed.
Actually very simple. (IMHO)