Best level to farm for gold is plasma pyramid if you are under 63. Any of the AO maps will do though. However since I farm for pots at the same time Plasma is my map of choice. I can go in with 0 pots and about the time I get to the first room I've got my quota of 25 of each.

I think that humania is probably better if you are liquidating all drops except pinks. But of course you have to be lvl 63 to get in there. I haven't checked out the drop rate on pots yet. I plan on doing that sometime this week.