Send him hunting, no doubt, which is the classic fairy tale means of getting him out of the castle. Was musing on happening to read about Polish nobility and their hunting practices, and how proudly they stuck to old-fashioned ones, whatever was happening in Versailles or other locations west, because it showed they had not lost their vigor and courage and all that.
Then I pondered -- hmmm, is there anything else he could be doing? After all, that wasn't the only reason kings left their castle -- and this story is not trying to push the fairy tale tropes into farce. A progress would be unsuitable since it would mean he would come by once.
But it wasn't as if I had tied the hunting into anything else in the plot. . . .
Whereupon the muse started to burble about the classic hunts for a white or golden deer, and how it can lead the king astray and lead to further problems. -- even if that would raise point-of-view issues for the story.
ah, the back and forward of working out the story.