I think you may be thinking of it in the wrong way. Don't think of it as getting closer, think of making features at the scale you want to see them at. A terrain large and in the background can be a mountain. One small and up close (or with a tin can next to it) can be a molehill :-) The rest of what you are talking about, grass, sand, etc. is just a matter of textures. Also, it is a common trap to think that all the terrains produced by Bryce are just the default mountain shape. Play around with the other Fractals, and you'll probably find a piece of ground like what you are looking for. Does that make any sense?