I am not too experienced with three player, but what I see is an ugly kingdom with little synergy. In a case like this I would usually try to play fluidly, taking mostly coin and maybe a couple of actions when it is convenient to do so.
Menagerie, KC ans Peddler are the "stars" of this set, but they really don't have much going for them in the way of support. Smugglers is an okay card if there are certain piles that you know are going to be rushed, like Laboratory or Grand Market, but i don't see any reason to buy one here. Merchant Ship and Saboteur are usually sub-par choices and I will only buy them if I see a great reason to do so. Fortune Teller is not horrible, but it is not a swing card. Mint. Well, Mint I would buy in this setup IF I drew five coppers, but otherwise, no.
In the end I would probably buy one Merchant Ship, one Fortune Teller, two or so Silver before switching to Menagerie on hands of less than six coin and Gold. Might consider Duke rush depending on how the tempo goes.
The reason JoAT won this game, in my opinion, is that his early buys were focused more on improving his own deck, while the two of you putzed around buying cards like Saboteur, Village and Smugglers. Don't get me wrong, these are good buys sometimes. Not on this Kingdom. I would have skipped the KC altogether and gone more Big Money, but it worked for him.
IMHO
--- Japofalltrades's turn 16 ---
Japofalltrades plays a King's Court.
... and plays a King's Court.
... ... but plays no action with it.
... and plays the King's Court again.
... ... but plays no action with it.
... and plays the King's Court a third time.
... ... but plays no action with it.
Japofalltrades plays a Gold.
Japofalltrades buys a Village.
(Japofalltrades draws: a Fortune Teller, 3 Coppers, and a Merchant Ship.)