I like the card a lot. I don't see any problems in relation to Cache - the chance of these two cards showing up together is slim in the first place, and cards shouldn't be designed strictly based on a combo with a single unique card.
It would be one thing if this comboed with Villages in such a way that no other Treasure card were worth buying - obviously that makes no sense in this context, but the point is that the Village mechanic of +2 actions and +1 card is extremely common, whereas the mechanic of Cache is exactly unique. Therefore don't design specifically around that one pairing.
That said, cost of $1 on this card has interesting implications with TfB in the midgame. It's a Copper that you can Remake into a Haven, Pawn or Estate. That's an interesting usage because you can use it very early to leapfrog into good stuff, then get rid of it for a benefit in the midgame.
I love that you can hit $5 no matter what your draw, however a real danger is actually hitting $6 on the 5/2 split. Try playing with a 6 Copper/1 Silver/3 Estate start one time and you'll see what I mean. Starting with a Gold is REALLY strong, and so is something like Border Village + Torturer/Mountebank or similar. If I picked one concern with the card, it'd be the 6/2 start. Everything else seems completely fine.