Originally Posted by
DesertNomad
Well, yes, overland, and to North Korea, but not across the DMZ...
Iran to Pakistan to China, then into North Korea, back to China and either by ferry or air to South Korea. I know there used to be a China->South Korea ferry but not sure if it is still running.
The real trip is Tehran to Pyongyang overland... but ICN is the closest point to get a SkyTeam return to the US and onward to Europe.
Plenty of ferry options from China to Incheon at this moment, most departing points are in cities near Beijing. There are also ferries from various points in China to Japan if you are interested. Of course, there are also daily ferries between Korea and Japan, in case you want to lengthen your overland tour by a little bit.