I contour traced the Niagara peninsula in the GIMP from a Google Earth image, and drew in all the rivers and water. This was something I would have never tried without my new Wacom tablet. This gave me a clean base-map to work with as the areal photo was too cluttered. I oriented the map so E is up.
I then added a bit of antiquing, a few more rivers, and a light bump map to highlight the terrain and the escarpment. I jumped over to Inkscape with a jpg of the map and started drawing trail and cities. Imported them back into the Gimp as paths, stroked them and started colouring. As the map is slightly more realistic than symbolic, I hadn't yet decided if I was going to add tree/grassland/forest/scrub type symbols.
The roads were imported as a SVG to a merged path. I just stroked the path with a 4 px solid line, then re-stroked the same path with a white dashed line. The road layer was set to a multiply (IIR) blend mode. The rivers are kind of indented. I drew a height-field map of the area, then subtracted a blurred copy of the river layer from that, so when I applied the bump map to the main land layer it effectively embossed all the rivers. I also added a blurred copy of the rivers (and roads) to my layer mask for the colouring so there would be a barely perceptible clear area around them. This gave them a bit more punch.
I then added some labels and pumped up the colours with another wash layer...I changes the water style (it was originally a woodcut effect) and added the escarpment (more fun with Inkscape.....path along path is very cool BTW), a title, and a compass rose with East (represented by a cross) as up. Here is the final image: