Personally, I don't think there are any 'good' options when it comes to NK.
The best option, though legally somewhat murky, may be something along the lines of the Stuxnet operation against Iran. Granted, the starting position is not quite the same, but I'm reasonably certain that their nuclear arsenal could be disabled with the right approach. Which should hopefully take nukes off the table on the other end, too.
Risky, but IMO preferable to actual armed conflict as it allows some wiggle room for serious back room diplomacy and limits the maximum potential damage done.
That's always assuming the dear dogs don't go back to sleep and can be left to lie, wich would be much preferrable to any other option.