I wouldn't actually put the text on a physical card... I'd just have whatever version I'm playtesting available for easy reference (like on a computer screen nearby the board visible to all players) and use blank cards as proxies....
Edit: So I should remove the +Buy?
As a general rule of thumb, if the text wouldn't fit on a regular card, you probably have too much stuff going on, no matter how you actually test the card out.
The +Buy is not the problem. The problem is that right now you have two or more half-baked concepts here that you are cramming together into one card. You've got your lab-with-penalty (or is it village-with-penalty now?) and you've got your copper-counting alt VP. There's no compelling reason to put them together; doing so just makes it messy and overly complicated. Try working on each one separately. I've already given some criticisms on the copper-counting (I don't think it can work).
Try laying out what your core concept is in a single phrase. For example, looking at your original iteration in the OP, I'd say that Mountain Range was meant to be
a cheap but powerful card that's still a pain to gain. It's better than Lab in your deck, but it has an on-buy penalty of 2 top-decked coppers. You made it even harder to gain with the copper and virtual coin restriction. Soon after, you thought about adding a restriction so that it wouldn't work with gainers, which still fits with that core concept.
You can iterate on it from there. The VP value does nothing but artificially increase the card's power. Is that really necessary? If the card isn't strong enough as is, you can just make it more powerful without tacking on VP. Are the buy restrictions OK, or are they too complicated? Are they strict enough, or too lenient? Are there simpler or more interesting ways to phrase them?