I went ahead and primed both roof panel interiors. Let dry.
Don't waste your time trying to wallpaper the back roof panel. The interior area is way too thin as half the panel is interior wall and the other half is exterior eaves. I suggest you just paint it a complimentary color. I am going to choose white because all of my interior trim is white. This area of the roof will only be visible when you look in through the attic windows. You still wouldn't want to leave it as raw wood though. You should paint it.
The front panel is different. It is completely viewable through the back of the dollhouse because it will make the front wall of your attic.
Dry fit it to your dollhouse so you can mark with a pencil where the eaves are and where the second floor partition wall divides the panel. Each side is a different room so you want to match your wallpaper patterns accordingly.
Once you wallpaper your pattern and paint your eaves, you can install your roof. This roof goes in easy but you must use a rubber mallet to make sure the wall tabs go into the roof slots. You need a nice tight fit all along the seams. Clamp with masking tape until dry.
