You get 10 gold every 5 min for the first 2 hours. After 2 hours playing with the same person, you start to get 100 gold every 5 min.
If you have a second controller/account, you can do this locally. Get the second account past the initial part of the game and then join it with your main account. If you have wired controllers (or the play-n-charge cable) you can just walk-away for a few hours.