To be honest there is no really nice feature in kicad (yet) for such a usecase.
But you could look into append board.
The guys over at this forum have laid out a nice workflow:
http://www.eevblog.com/forum/kicad/copying-layout-portions-in-pcbnewkicad/
Maybe it is something you might want to look into.
By the way if you have problems opening pcbnew/eeschem as standalone look at this thread: