I once tried building an engine payloading mass Bridge off of Shanty Town and Patrol.

The math: playing Shanty Town plus Patrol nets one card. To play n Bridges I need to play n-1 villages; for n=5 I need to draw 4 cards, for which I need 4xShanty+4xPatrol (and I need to not draw whatever trasher is stuck in my deck). Note that n=6 requires 5xShanty for the payload and 6xShanty to draw all that with Patrol; only cheaters buy 11xShanty.

So that's a deck of 8xShanty, 4xPatrol, 5xBridge, a trasher, and probably an extra Shanty/Patrol pair to draw past the trasher, which is obviously super fast to build. Note that this is enough to single Province. I can probably add in a Gold if I add an extra Shanty/Patrol pair to draw it, to double Province.

Of course, you should continue adding Shanty/Patrol pairs as you green to draw past your green cards.

That was an unmitigated disaster, but it's great fun retrospectively