I tought i poste some update on this one as i used to farm it before patch 5.0 and after that too.So here are my toughts about soloing Gnomeregan for the +2 scope:
1.The 2pack mobs you cant separate-pull anymore,they are tied together.Bummer.
2.The 3rd box is soloable as well.Haven't tried the 4th yet,but will go for it,and post it in an update,if its possible.
Here is what i did to get to the 3rd box:
After i soloed the first 2,i tought i'll venture more deep inside to see,how far i can get.
There is a 3pack on the first floor,that i had to take out,to reach to the lower level(Dormitory).
I sent my pet in(Bear),got aggro on all 3 with thunderstomp,then pulled the melee one,kited him back to the location of the 2nd box.
Meanwhile my pet died(with the melee mob toghether),and i just pillar-kited the casters.
Was pretty easy,just kept serpent sting on both,and hid behind the pillars when they started to cast.
Then i went down the stairs to the Clean Zone.
Pro tip: here are some caster npc's,who give you stamina buff,if you fight next to them,which you can't avoid anyway,if you consider going further into the Dormitory.
There are 2 or 3 2packs,and a loner patrol that i took out,and i ventured deeper to see if there is a box in the alcoves.Now there is an alcove on the 2nd "floor" right opposite the entrance with a 3pack.
I sent my pet in, who gained aggro,while i looted the box,and got away with the loot

Did this run 2times,1st time i got the +1scope,2nd time i got the +2. My hit gear had a 15.71%,my hp was 1.8k.
Happy hunting and good luck farming the 3rd box,as it is tough as shit to get there,but worth, believe me
