The 2009 Doctor Who specials has to have something tying them together, so how about this;
The Planet of the Dead bus has a poster Neon by Naismith on it. The book the Doctor is carrying in the Christmas episode is called Fighting The Future by Joshua Naismith, and we see Joshua Naismith being attacked by a CGI enemy during filming too!
And Joshua Naismith has all the letters of John Smith in it too!
So is A Journal of Impossible Things a red herring