Yep - it all scales together - cameras, lights and objects. In fact unless you intentionally leave one object in your scene unparented as a reference point, when you scale up the box, you will see no noticible change in the preview window. But don't be fooled by the fact that it looks like nothing has changed, because the NUMBERS have been changed even though the relative aspects of the scene appear to be the same. BUT there is one little caveat: When you first parent the camera to the box, it will shift position. You must correct that BEFORE you scale the scene up, so after parenting the camera to the box, re-position it, and then scale the scene up - everything stays in its relative place.