Public Domain Wilderness Map Symbols

If nothing else, these might serve as models for your hand-drawn maps:

Here is a page from the book I got some of these from:

It seems you have to go back to the 1600s to get this kind of representational topography we like in our fantasy maps.

As you can see, I'm going for the old, hand-drawn look but you might find these two books interesting for more modern campaigns:
German Military Symbols (1943)
Soviet Topographic Map Symbols (1958)