All's well that ends well in Hoot.
And it ends really well for Roy. In the last scene, we see him soaking in some Florida rays while cheering on Beatrice at one of her soccer games. Roy chuckles as he recognizes the irony in "Beatrice the Bear waving at Tex, the new kid" (Epilogue.53). That's not something we saw coming from page one.
But Roy doesn't stay for long—he goes to the hidden creek that Mullet Fingers showed him.
While there, he attempts to catch some mullets of his own. Needless to say, he comes up empty-handed and is convinced that the feat is impossible and that Mullet Fingers had tricked him.
Now, two significant things happen here. First Roy hears something. But not just anything something. He thinks he hears a laugh. Could it be Mullet Fingers (who has since run away, yet again)? Unfortunately, we never find out.
But when Roy goes to collect his shoes he notices that a mullet somehow ended up swimming in one. Not only does Roy admit that catching mullets is possible, he resolves to try again like "a real Florida boy would do" (Epilogue.79).
That's quite the change from a boy who dreamt of going back to Montana. In fact, the Roy we see at the end of Hoot is very different from the boy we're introduced to in Chapter 1. It might have taken a while (like pretty much the entire book) but Roy finally adjusted to living in Florida.