Not sure that's a good thing. I heard they were already stretching it out and adding stuff to get two movies. I suspect the final product will not resemble the book much. Oh well, should be entertaining to watch anyway.
My understanding is that they will be using material from the LOTR appendices to supplement The Hobbit
itself. That material ties together the two stories, and from a cinematic perspective it makes a lot of sense to do that. Will it be totally true to The Hobbit
and only The Hobbit
? No, but I think Peter Jackson has earned the benefit of the doubt with the his masterful treatment of Tolkien to this point.