This is how I would go about it. On the first night when the winds are blowing north, launch a tactical nuke strike of the front lines and take out every piece of Nork artillery and most of the Nork army in one fell swoop. At that point, nothing can come south without being destroyed by radiation.
By doing this, civilian populations are unharmed or damage is minimal while at the same time the North’s fighting capability and 60 year old strategy is gone. If Kim decides to launch a missile at the US, Japan or South Korea, ABM batteries are spun up and a secondary launch prepared once the North’s missile(s) are shot out of the sky or destroyed in their launchers. The US counter strike then is aimed at the North’s leadership since they will all be with Kim.
The entire war won’t last more than an hour, millions of civilians are spared death and China can clean up the mess. There would be no way in hell that the UN will declare the US committed crimes against humanity since the strike was designed to preserve humanity, unlike 100,000 artillery pieces aimed at the civilian population of Seoul.
I like your idea. It's akin to what I have been saying. Except instead of launching a first strike I would just shoot down every test missile they launch. There may not even be a war once they see none of their missiles will get through. If they are stupid enough to proceed then we go ahead with a plan like yours and strike first. The key IMO is to allow them to launch first and make it clear to world we are acting defensively.
I don't believe Trump will launch a first strike as it is. It is difficult to prove after the fact what an enemy like NK would have done if we had not struck first. I think Trump wants to prod NK into making the first move. I say let NK launch first but destroy every missile they launch in the air over open sea.