As I own Bryce and Carrera as well as Fractal Terrains I would most likely use one of those.

I would take a gray scale elevation map of the area and insert it into the appropriate program as a height map. Pure white would be the highest and black the lowest points. The 3D app would take care of the rest.

I would then probably cheat and simply overlay the full color map of the area on top of the 3D map after removing text and such.

If I was really feeling creative, I would convert my full color map into gray scale and use that as an additional height map to actually create the buildings and such.