The Hobbit on Facebook "So, Mr. McDuck...You say you can swim in this?"
This would appear to be Bilbo already in Smaug's treasure room, which, if it happens in The Desolation of Smaug, would suggest that the dragon's tale will be wrapped up by the end of the second installment, leaving part 3 - There and Back Again - to deal with the Battle of the Five Armies and whatever other prequelly stuff is needed to establish the re-rise of Sauron. And of course, in true Peter Jackson/LOTR tradition, there have to be seven consecutive endings too.
Side note - have you noticed that nearly all the Hobbit toys in stores now feature stuff that hasn't happened yet in the movies? Mirkwood, Bolg, the barrels...kids who don't know the book might be confused this Christmas.
Feel free to speculate irresponsibly. It's what we do.