i have done 3 on mannoroth, mostly with no help. i always log early, chest has dropped 2 minutes early at times. i also go to WHO and type: stranglethorn vale. this lets me know at least who of the same faction is in the area and who to look for. also you know by whispering them, what 80's are going for trinket or chest, and can maybe ask or cut deals. 12PM, 3AM, 6AM, 9AM generally are alot of no shows. if you aren't concerned with achievements on other players, when blizz does events like the bountiful harvest, my friend got his paladin done in 2 days. i was going to do it then, but didn't want to hinder a friend and guildie. much of this involves taking your player there and leaving them there till done, whether it takes 2 days or 3 weeks
have AGM
-38 warrior...was a 29 twink
-19 rogue
-13 rogue
need
-19 hunter
no longer need
-29 rogue
-39 druid
on my alliance side, all need AGM
-19 rogue
-19 hunter
-11 shammy
-11 druid
i still play my twinks even if they don't have it, it's the same thing with fishing hats. sorta glad they killed 29/39/etc twinking on RUIN...no rush there and my once 29 paladin is at 48 where the AGM is a non-issue IMO