MOC Help

Hey y'all, I wanted to get some feedback from y'all about this MOC. It's the snow scene from the Clone Wars episode Victory and Death. The area I'm working with is a 23x32 stud area, but I'm running into a design block on how to finalize it. I have a general idea of how to display the helmet, but as far as building the landscape and the arch in the background of Vader, I'm drawing a blank. I've combed rebrickable for snow/landscape ideas, but none were that helpful. So any ideas or things...