Gear/Plan
Get rid of those pesky Estates while you pick up your three Gears.
I've been playing around with this lately. It's really strong as a standalone money strategy (if there aren't crippling attacks or good engine Alt VP). It's extraordinarily consistent - more so than any money strategy I've played.
Turn 1: Plan on Gear.
Turn 2: Buy Gear and trash Estate.
Your deck is exactly 7 Copper, 2 Estates, and a Gear.
Over the next 4 turns, your goals are (in priority order):
1) Buy two Gears and trash two Estates.
2) Buy two Golds.
There is a very high likelihood (~86.5%) that you will accomplish these goals.
There are exactly three failure cases:
A. You draw 5 Copper on turn 3. (Likelihood: 8.3%)
B. You draw 3 Copper and 2 Estates on turn 3 (buying Gear and trashing Estate). Then, your turn 4 Gear draws Copper and Gear. (Likelihood: 4.2%)
C. You draw 4 Copper and a Gear and draw 2 Copper on turn 3 (buying Gold). Then, you draw 1 Gold, 2 Copper, and 2 Estates on turn 4 (buying Gear and trashing Estate). Then, you draw 5 Copper on turn 5 or Gear draws Gear. (Likelihood: < 1%)
These are not catastrophic failures. In each of these cases, you should probably buy a Gear and trash Copper. Now you spend the rest of the game with one more Estate and one fewer Copper than usual. This might even help in the mirror (though you're disadvantaged if it comes to Duchy-dancing).
Turns 7+: Buy Province when able, buy a third Gold on the first miss.
I tested this out and consistently got 5 Provinces by turn 12. After that, the deck starts to falter, but you can go in for Duchies or save up for Provinces depending on the game state.
In a mirror, it might make sense to skip the third Gold and go for Duchies immediately. Maybe.