First of all you should reverse all those ‘back faces’. After you change one of the faces via Right Click > Reverse Face, you can then right click the face you reversed and choose 'Orient Faces’. (You can check this in monochrome style. Back faces are shown in blueish color by default and ‘front faces’ are white. Back faces are evil, avoid them)
Basically everything that human eye can see must be front face (white) in SketchUp.
- So i assigned default material to get rid of the texture from back face and reassigned roof material. That also fixed the side problem you face. (If you somehow still get the issue in the process, Right Click to face > Texture > Reset Position)
- and 3.
Your model is messy. There are a lot of stray edges and polygons are not properly created. Those stray edges cause the outline you see in the interior and facade. Clean them with CleanUp³ extension. Also Solid Inspector² extension will come in handy in the process. It detects and fixes most of the problem or tell you what & where the problem is.
Here is the .skp i modified : russell_house.skp (674.0 KB)