EDIT: Before vote negative PLS comment first
The "Normal" Method
The normal boost method is. Play to Inferno akt 3 on EASY
Get around 200+% gold find
A pickup radius of round 30 inch/yard/meters
Backtrack from the Waypoint "The Keep Depths Level 3"
in the Bastion back to Level 1.
With this setting i get around 100-150k gold in one hour. Round 50 Hours later and the achievement is done.
The "Ultra FAST" Method
I found out in a private Co-Op Session on one console with a friend and two 60 Champions that, when you play the game in Co-Op there is no split screen and there is NO "Single" loot. ALL the items and gold
in the session drops for ALL players and ALL players can grab it
. But the best and funniest part is that it looks like that magic and gold find are "Stacked" from ALL characters for ALL characters.
With a second player i found round 400-500k gold in ONE hour. If you can get 4 Co-Op players on ONE console together and they have all 4 round 200+% gold find and only ONE grab the gold, with a high pickup ratio, then you can get this achievement ultra fast and very easy.
With this method i got the chevo in round 17 Hours playing.
If you play Co-Op you can play ALONE with 2-4 connected controllers the other players follow your champion the hole time :D
That's the solved mystery
Have fun and good luck to boost this Achievement :)
If you work on this achievement you get automatically the
Edit: Gold find and boosting for gold is in every difficulty best in akt 3 in my opinion :)