Well if you’re aiming for the North Korean border as the original post suggested then you’re likely targeting railroad infrastructure. To get to the NK border you have to go a long roundabout route to avoid encroaching on Chinese airspace. Taking out train choke points even half way closer to Ukraine would be a lot easier, and still cause a lot of disruption of supplies from NK. I’m sure there are plenty of bridges, tunnels, etc. that could be targeted.