Hm. Interesting. Here are the viable options I see.
Option 1 is Courtyard-BM. Always an option.
Option 2 is a Laboratory engine with KC and outpost. Load up on laboratories, add in a market square for a +buy, end the turn with outpost so you can have a second turn. Use KC to supercharge it so you can draw everything well, and possibly add in a single courtyard to play as your last action of the non-outpost turn to guarantee that your outpost turn starts up with a lab in hand. If you have a spare lab
Things going for the engine: KC, Outpost, and alt-VP with Gardens. Things going against the engine - the +buy is out of the way, since there's no trashing for the Market Square to be activated reliably and no villages to use the CR for draw reliably (until you're already KCing labs). No villages besides KC. No attacks to slow the game down.
Options that are technically there but not really good IMO:
1) Market Square/Gardens and Market Square/Counting House both look like combos but I think would be fairly mediocre compared to BM-courtyard.
2) Engine with terminal draw doesn't really work because the only village is KC, I don't think you can get enough KCs and cantrips to reliably start a turn with KC-cantrip-terminal draw or KC-kc-terminal draw on an outpost turn. Especially with no trashing and no source of money on actions.
So, BM-courtyard or KC-lab-outpost- engine... tough choice. I'm having a hard time envisioning how long the engine would take to come together. The components it needs are probably about 6-8 labs, 1 outpost, 3-5 kcs, a market square, 3-4 extra treasures, and it would probably end with 3 provinces/6-7 duchies/gardens... Idunno, counting like that it seems like the engine would be just a tad too slow to pick everything up, and once it started greening it would sputter on its outpost turns. And you can't really make it a megaturn because there's no virtual coin to KC.
So I would lean courtyard-BM. Get labs on $5 hands, especially if your opponent is going engine too few labs might mess them up.