I think the talks that will take place between N. and S. Korea will likely be the most productive ever. Kim is not crazy, he plays being so in a desperate ploy to keep the rest of the world from crushing him- and so far it has worked. Now that he has nukes, he has gone from belligerent boy king to an actual danger. He is in a more precarious place now, and he knows it. He also knows that should he start a war, he and the Kim family (he is not the sole player) will all die.
Kim is evil, and does horrid things to his own people, but I think his tweet war with Trump is histrionics. He now knows there is someone in the White House willing to call his bluff, and hence the opening of the hotline between N. and South. This would not have happened under Clinton, it would have been more appeasement.
Whether we are heading to war or not will be seen in the next NK missile launch. If Kim launches an ICBM that is aimed at the US or Guam, we will attempt to shoot it down. Then it will hit the fan in earnest.
Otherwise, another year’s GDP of NK will arc up and splash in the ocean. More sabre rattling, and talks in the background. What I hope Kim understands, is that when a convincing case that he is about to have deliverable MIRVs can be made, so will war.