this map project in my space at the antique mall a few years ago, before I had my own shop,  came about because I had bare ugly walls there and a big old box of maps from my grandpa.  most of the maps were vintage national geographic maps and old midcentury road travel maps.  i knew most of them would be covered up but I also knew that they would provide a lovely layered and textured backdrop.  i used wallpaper paste to adhere them and it was easy.  decoupage with maps would be a great treatment for any small space, especially if you can get your hands on some vintage ephemera to use!