There are several routes.
The challenge is, it is hard to let go of the Cubs really-good-but-not-good-enough-to contend core. They have so many 2 win players and one need to be upgraded to a 4 win player.
The problem in this is that we see upside in a 2-win player like Busch and ZiPs sees 4 win potential in a player like Hoerner. So who do you try to upgrade. And if you trade a 2-4 win position player for a 2-4 win pitcher, you create a big hole at a position like first or second, and all your depth is in the outfield (besides Shaw, who you are already, ostensibly, counting on for 3B.
Quality floor but no star power or depth in the starting lineup.
Depth but no big WAR in the rotation.
It is a great starting point. But I don't think you can put this team over the top by just trades. There has to be FA incoming.