Printed the cards and have begun testing!
First game had secret society, stronghold, scenic village, reinforcements, and trading vessel.
Scenic Village: Seems powerful enough that it might be worth dropping the card. Infinite actions is pretty darn good, but I might be overrating it a bit.
Stronghold: Unintended consequence of giving you +1 coin on the turn you play, will switch to at the start of your turn probably.
Reinforcements: Pretty good. This game had highway and highwayman in the secret society deck and so the +buy was more useful than in most games, even after you play it twice. -1 card is usually better in early game but it's fun when you can deny them a province.
Trading Vessel: Needs testing in a game without cost reduction. I wonder how it would work with the gain a silver and trash a card swapped.