I would say go to Valde pit and kill all the oozes and spiders even with or west of Frostcrypt. Anything to the East of FC will summon.
These mobs have ~70k hps which is less than the Icefall mobs, are usually well spaced and there are about a dozen to kill before respawn. They oozes are social with each other, but have relatively small aggro ranges and the spiders are aggressive. There is only one roamer that covers most of the West Pit, and then another to the north of FC that only paths in a small area.
Im bored so I'll make a drawing!
* Just drew this at work based off my memory of hunting there pre-SoF. Should be close though
** All X's can spawn as either a spider(73-76) or ooze(72-74).
Now for the two downsides to hunting here:
1) Sometimes when you arrive a few oozes are in social range of each other. You can either avoid these or use VP and zoning into FC to split them - or just kill two at the same time if you VP one and root other.
2) Respawns.... are very odd. Whenever a ooze respawns, they will automatically move to where you are standing and sit on you for about a minute before going back to thier spawn location. Due to this , when its close to respawn time you should always stay social range width away from any ooze you are killing and make sure to VP them towards the walls to make sure the respawns dont aggro you while pathing to sit on you. Dont get scared though - they are harmless if you know what you're doing, it's just odd.
Bonus!!! You can get the zonewide rare - nice AC aug (I had 4 drop there over the course of 7 levels and a couple hundred aa - one for me, one for a guildie, one for my SK box and one for a lucky passerby) and also a nice shoulder item
Hope that helps!!!