Amusing! I like the idea of replacing the uninteresting foggy sky. Replacing the foggy hilltops as well would be more convincing than the pixelated edge you created between earth and sky, however. The rolled up path should not have a shadow along the top edge and the side shadows should be much reduced (note the negligible shadows of the fencing posts). Lorry perspective is off: Draw lines along the outer edges of the pathway to determine the scene's vanishing point. Cut out the side of the lorry and distort it so that its top and bottom edges point to the same vanishing point. Do the same with the top and bottom edges of the text.

Text perspective of the truck container is wrong.

Fix the shadow on the rolled up path. It wouldn't have a shadow on the right side.

The revised text matches the lorry much better, but unfortunately the lorry still doesn't match the perspective of the scene -- specifically see http://www.pxleyes.com/picture/26232/4c8595c077639.html for how the vanishing points don't match up (bright lines good, dark lines bad).