Don't ever underestimate the propaganda bandwidth of a rusty barge loaded with select few.
The passengers will be workers who are good at working or at pretending to work well. Perhaps a lottery will be involved to further inflame the passion. The lucky (?) winners will be given free tickets, their departures will be celebrated with TV and other media present, as well as their return (if it comes to that.) The said workers will then give ecstatic interviews, will thank The Beloved Leader for the honor and will otherwise participate in propaganda efforts. Refuseniks will be shot, of course.
North Korean TV apparently airs a few hours an evening, almost all old propaganda films.