Uunfortunately, explaining it doesn't mean it makes any more sense. Aside from a few minor details, the time between the end of the war and Naruto's Hokage years is a big gap in the story. In the novels it gives a first-person view of some activity each character engaged in during those years, allowing you to fill in a bigger picture. Such as, Kakashi sent all the ninja on a top-secret mission to get gifts for Naruto's wedding. Things like that.
But as far as indepth reasoning and rationale, there is none. And, imho, Naruto gets the worst of it. We are never really told why Kakashi came before Naruto, how Naruto felt about it, what prompted Kakashi to retire when he was still relatively young, and what exactly Naruto does as Hokage that makes him different from the rest of the kages and shows he still has his 'ninja way.' It's an important point that was touched on again and again in the first half of the manga. But it's entirely skipped over in the end. Naruto's role after the manga ending is almost completely in reaction to everyone else. It seems there no direct or meaningful emotional moments from him. No true development. Just the other characters developing, and Naruto moving along with it like a secondary character.
Sorry to be disappointing, but to me it is lacking a lot.
There's more info in the novel threads, if you're interested. Each one has a good summary that will fill you in on what happened with each character in the interim time. And the novels are still coming out - I think Shikamaru is next? - so if you like them, it's still going on.
So yes, the timeline is screwy. But even if it were straightforward, the story itself is just without heart anymore.
That last part in particular is what I feel is making this such B.S., Tricks. It takes away from the heart it had before the war arc and before the rest of the crap that made it into what it is now. X_X
