I honestly wouldn't be surprised if Jackson had the guts to throw in some more chases after the BO5A and story conclusion in Erebor. He'll probably extend the standoff between the Company and Bard's men, BO5A after that when the Elves and Dwarves arrive, and then whatever shenanigans he can make up when Bilbo is going home. He might even throw in a Nazgul encounter as a 'foreshadowing' of Fellowship of the Ring.
Some of his additions might be good for sets, but I'm honestly starting to understand why Christopher Tolkien hates these movies, or at the very least this trilogy.