well, i have read on some post's about using sheet styrene, and in the inside corners, using 'square' styrene rod, this way you can sand the corners down just like the real cab, slide over to the scale auot mag forums, there is a thread on this in the 'truck/commercial' catagory by a guy called " zoli " , check his stuff out, he's the main man at this type of building... good luck go here, www.scaleautomag.com