Yes, you can make a good model, using paper techniques.
To create the contours quickly and easily, cut corrugated card (packaging) into the desired shapes.  For a tall mountain, for example, you would use several layers glued to each other, each smaller than the last.
Make a smooth pulp (see the recipes in the articles section) and smooth it over until you have the shape you want.  Don't let this get any wetter than it has to be or you will wait a long time for it to dry.
DavidO