I'll let others give the important advice with Keep, as I haven't played with it too many times yet, but trashing coppers (on most boards anyways), should still be a priority; it doesn't matter if you're giving up 5 VP early on, opening with 5 Great Halls wasn't the greatest of strategies. In the endgame, if you have extra cheap buys, that's when you can start regaining coppers. But timing's probably pretty crucial: too early, and you won't be able to Province anymore, too late, and you'll lose the Copper Keep. If you have fewer extra buys, then you can start Yellowing earlier, as you won't be junking your deck as much.
Like you, I also don't really know how to play around the Silver/Gold/Kingdom Treasure piles, so I'm not going to try to explain when/how much you focus on gaining those. What I do think is true is don't get content being tied, or even +1, on a treasure pile - try and make sure you've secured those 5 VP and your opponent can't also get them. After all, that's pretty dang close to Province level, not counting the actual impact of having treasures in your deck.
Ultimately, Keep encourages Big Money, or at least an engine with treasure as payload, but you still have to evaluate how strong/quick the engine is. As you've seen, 5 points per pile is a lot, and I expect it to be up high when the Landmark rankings come out (Qvist!! But seriously, no rush).