Scenery Challenge, camouflage opening

[railandsail]

Please step forward all of you fellows that are knowledgeable about scenery.

I'm trying to place a Walthers 'New River Coal Mining' structure into the upper deck, back left corner of my layout. A portion of it would sit over the double crossover fixture I made, while the loading tracks themselves would be out on a 'flat' like I show in these photos,...the foam flat

 

 
Two of the most immediate questions that come to mind:

1. Is it possible the 'camouflage' that opening in the rear wall that is bringing a single line track into the room from the outdoor helix? Is it possible to make that NOT look like a tunnel entrance??
   
2. In that same sort of vein, is it possible to create a 'fake background scene' on a small portion of that rear wall would appear to be a track (or several of them) coming in to the loading tracks for the coal cars?...(at the wall end of those straight pieces of track I laid down there)
   
    
   

 
Sorry for the rather crude mock up