Grainy Landscape is a preset that you can use in Silver Efex that gives the photo an old look and a nice soft grain. I made the preset for use with landscapes, but of course it can also be used for other purposes, you can try that for yourself (I haven't done that yet). You can download the preset below. Install it in Silver Efex. At the bottom of this article is a link to a brief instruction how to install presets.
An example of the before and after situation: