So recommended going there already at 40? Cause another guide i read says this 44 - 50: This is another GREAT spot. After completing the main questline, head to Coldhabour. There's a portal to the Cliffs of Failure in the northeast that teleports you to a place with lots of 2-packs. Here you want to multi-pull as many 2-packs as you can - there's one spot where I could pull four 2-packs simultaneously with little difficulty.
I am mostly going with another friend tho since it doesnt hinder the xp gain anyway. Atm i am 37, and doing 37 - 44: In southern Reaper's March, there's a place called Moonmont with lots of 3-packs. The most optimal circuit I could figure out had me clearing the top of Moonmont and only jumping down to get a 3-pack by a bridge.
But i found that spot terrible since its like 10ppl running together in a circuit and i didnt even tag everymob / or didnt do enough dmg. So didnt get xp from everymob, and if getting xp from a mob it was ~~ 100xp from it.
Good idea about just porting to a person to avoid doing the quest tho!