My friend visited Korea (extensive description with pictures here), even visiting Geumgangsan. All this can be done, claims to the contrary notwithstanding. Commerce is sowing the seeds of peace, as it always does. And North Korea and South Korea don't need the US government to make this possible.
Read his full travelogue to learn about the DPRK border crossing, darkness at night, propagandist monuments, and talking "insulting photos".