You can start wallpapering the dollhouse now, but you'll need to leave the attic for later since the front attic walls are part of the roof, which can't be installed yet. You can wallpaper all the side walls.
Wallpapering this dollhouse is a bit tricky because of the window mullions. You want to avoid covering them, so dry fit your wallpaper pieces first. Shine a lamp on the exterior of the dollhouse to help you see where the windows are, and use a pencil to outline them. Cut out the window openings before applying the wallpaper. Your cuts don't need to be perfect, but be careful. Laser-cut dollhouses have precise parts, so aim to cut close to the edges of the window openings so that the interior trim can cover any gaps effectively.
Instead of traditional dollhouse wallpaper, I’m using scrapbook paper in colors that complement the exterior of the dollhouse. Since I don’t plan to furnish the interior, this paper works well for creating a nice finished look, even if it doesn't have to scale prints.
I folded my wallpaper over the edge facing the front door of the first-floor partition because that edge will be visible when the operable front door is opened to reveal the staircase. While you could cover it with trim like the back edges, it won't look as good.
