Taking the picks and shovels argument of how to prosper from a gold rush, I’d start hoarding mattresses. Once the banks have gone under and we’re in Mad Max territory, people are gonna need somewhere to stash all that bullion.
Why not go a step further and install a gold sensor in the mattress with a gps positioning system. That way when one of your purchasers stashes their gold … it could let you know and you could either call round and remove it from them or sell the gold location info on to some hired goons…
We need outside the box thinking in this day and age!!!