Good questions.
I googled “north korea tundra” and got a few results that look like a similar landscape, but nothing that says “bingo”.
I googled Kim Jong-un truck and nothing close. So I was thinking more about this and it occurs to me that it can be NK but not KJU. I remembered reading speculation that the elites were planning to ride out WW3 in NK, so if that were the case, maybe it’s an entrance to some other elite’s lavish underground bunker. Wild speculation on my part, but I consider it within the realm of possibility.
Speculation perhaps, but interesting. I’ve liked the way you think for a while.
P.S. Belated thanks for your links to the DOJ Criminal Resource Manual, the Fall of the Republic video and the Kevin S page.