Trump's foreign policy is not as "incoherent" as you claim. It essentially stresses several points:

1. Strong national defense as a deterrent (nothing shocking or new there)
2. US self-interest as opposed to nation-building, ideological moves or imperialism, which has a few corollaries:
   2a. Our allies need to pay their fair share of collective defense obligations (NATO, South Korea, Japan)
   2b. We should avoid getting involved in other peoples' problems (Syria, Iraq - 2003, probably Ukraine)
   2c. If we do have to get involved, we do what it takes to win and get the hell out (Iraq now probably)
   2d. Sometimes the dictator is better than the alternative (Syria, Iraq, Libya)
3. We shouldn't pull the rug out from under our allies (Egypt, Israel)

While Item 3 may at times seem to clash with some of Item 2, it's a fine balance.

If you don't believe that millions of lives have been destroyed by free trade, you haven't visited a lot of small towns in America. I lived in many of those small towns. The poverty has risen, health has declined, suicide rates are up dramatically, families are disrupted as a result, and a smart trade policy can fix it.

Your statement that the problem is "not free trade itself but the way its rewards are distributed inside the USA" is a truism. It's like saying that gun violence is not a problem "with guns themselves but the way people use them to kill others". However, the very fact that you say "the way its rewards are distributed" betrays a Leftist approach to the issue. Trump is offering a free-market style solution that essentially will likely involve carrots and sticks to encourage more production in the US. This whole "retraining" bullshit was started under Bill Clinton and I see you're parroting it. But what do you retrain a Carrier air conditioning factory worker to do? Flip burgers? Mindlessly process mountains of useless medical records generated due to Obamacare? We can't sustain an economy on service jobs. We need to make shit too; in fact, the reason why the minimum wage is an issue now is because people realize that most service jobs are too fungible to pay a good wage (I'm obviously excepting licensed professional services).

We need more engineers, scientists, researchers, high-tech factories, and probably a bunch more semi-skilled factory jobs in low-tech areas too. While some industries were already doomed in the US 30 years ago, like low-quality steel, there are plenty of places where we could have saved jobs but didn't.

If Trump has the right people in place, and I firmly believe he does pick the right people and knows how to delegate, I think we can strike the right balance between free trade benefits and a bit more protection of US jobs. It's not an either/or dichotomy.