I just realised that Bishop would be pretty hardcore. You're very well set up to make the golden deck, and the trashing doesn't help your opponent.
Yeah, you can get it set up in 7 turns just buying money and the 1 Bishop. You chew through all 8 provinces and have 44 points on turn 15. That's pretty darn fast.
But if you really want to go fast...
Copper->Copper->Embargo->Bridge->Quarry->King's Court.
Turn 7, KC the Bridge, you now have $6 with 4 buys at -$3 (actions at -$5). Grab Mint/KC/Bridge.
Turn 8, KC/KC/Bridge/Bridge. Buy 6 Provinces and a Farmland, trashing the Mint and gaining a Province, for 44 points.
In a Colony game, on turn 8, you should grab 2 more KCs and Bridges, and 3 good drawing cards. All you need to do is draw 2 KCs with your draw and you should be able to get all the colonies at once.