How would I create a landscape and road system with a pre-drawn map?

So, say I have a pre drawn map that looks like this:

What would be the most efficient way of creating the landscape and road system in UE4? Would I have to create the terrain first in World Machine? Do I need to make an outline of the roads in Blender, then export that outline as an .fbx? (I tried that but it’s not very pretty or efficient.) Or would it just be best to eyeball it? Anyway, leave me your thoughts. Any feedback is very much appreciated. Thanks!

You probably want to build a level using heightmaps. You could use worldmachine or whatever to like as well. As for the roads, you might want to look into splines. If you want to create each section of the city as a whole in blender (with the streets), you could cut the model up and use level streaming.