I built my latest layout the way you suggest - with no cheating. For realism, you need to start with the terrain. I had specific ideas for how the terrain would look, including a large hill, tunnel, truss bridge and trestle bridge crossing above a low riverbank, and a town at an intermediate elevation. No track was put down until the terrain was designed and installed (but not necessarily with completed scenery). I'm not going to include any pictures now but I expect my layout article to be published in OGR soon. Also see my article about a scratch-built factory now appearing in OGR Run 300 (pages 51 and 19) for some pictures.
MELGAR