World wide trend is people love trills, trill seeking is booming, I think North concentration on tourism, its unique unwesternized and unique Korean culture. Korean traditional dish, hand crafts and shows and ordinary people daily life Korean traditional villages et al. Cult cultural is also big attraction, not many country has that, also should open bazaar-open markets that are uniquely locally made products, because of exchange rate a huge attraction for possible serve around South, Japan and Chinese and Russia... must be uniquely Korean. North attracting tourists, let the world come to North. North has plenty to offer i.e. life style is may be 60 or years behind but that is why that can be a great asset to selling points, a huge potential for world tourism, you have it flaunting it, it same time must be safe,people safe for going to North again again spend big dollar! Think about market size these immediate surrounding countries.
Update: If thing right it can be a great weekend holiday ( short daily, weekend) for people from South, that should be continues, probably all majority of people from South want that kind of trip!