This is the finished product, but it started out like this, lots of crumpled up paper bag pieces.
After I covered the whole front of the box, I covered it with wax paper, then placed it under a weight (a case of diapers) and allowed it to dry over night. The next day, it looked like this.
I dry brushed some brown acrylic paints in different shades, and then wiped them off with a dry paper towel. After everything was dry I went over the edges of the spine and around the edge with a finger nail file just to rough it up a bit and make it look a bit faded. A final inspection of any bag pieces that might have lifted around the edge, and the cover was done. All I had to do was glue my text block to the cover and Tada! Zombie Apocalypse Journal.