Take care of how?
They're soon to test a nuclear weapon and already play fun games testing missiles and having them land just off the coast of Japan. Not going to be fun once those things are nuclear missiles and en route to Tokyo.
The people are severely repressed, it's hard to imagine how much North Koreans suffer, look up Yeonmi Park's story.
What we seem to do is ignore these maniacs, until it's too late or it's absolutely critical, then they hold us hostage, like Putin.
(edit: another old article that points out inconsistencies in Yeonmi Park statements: https://thediplomat.com/2014/12/the-strange-tale-of-yeonmi-p... ... The JRE interview wasn't a fluke)
I don't think that you can reasonably treat Yeonmi Park as a reliable witness.
North Korea's train network is 4700km long, though it is not perfect... If you want to travel from Pyongyang to Chongjin for example, you're better off flying there
Sanctions against Russia aren't uniquely effective in a way that sanctions against NK aren't. It's just that the threat of having your economy look like North Korea's is pretty dire.