To just be a service to other gm's I would recommend adding fluff to your adventures even if the box set is linear. I assume that we wont be getting much in modules till the core book is released so if you are not setting the stage for a self made campaign you and you players will be disappointed with the games till then. I spend about two hours before our weekly session writting a outline of what I plan on rp'ing that night and I try to keep pc's focused on that and it for the most part works.