I read that the ship was moored at Wonsan, on the east coast, from 1968 until the late 1990's, when it was disguised as a freighter and moved to the west coast so it could be put on display near the capital. Given our surveillance capabilities, it's amazing that they could have pulled this off--but remember, this happened during Clinton's presidency.
Under Xlintoon's watch they could have sent it by way of the Air Force Adademy, West Point, the Naval Academy and Potomac and no would have been the wiser!!