Probably stamp papers all day. More than fighting and murder, to be the leader of anything financial, especially of something the size and worth of a ninja village, management is important. That includes reviewing and signing large amounts of documents. Not what he expected, but considering Naruto's childlike personality I am sure he imagines each paper as an enemy that he has to talk down and practices his inspiring speeches. Obviously this would be time consuming and unproductive so we have the actual hokage, Shikamaru, actually running the villages infrastructure. Naruto in his office is just a well intentioned, but unproductive bench player waiting for his next chance to break out of his cage to relive his more blood-pumping, glory days. And that is, in its own way, a very awesome way to be.
What do you think?
