I've created something approaching a working method of adding a road to some simple terrain.
I'm using a pair of techniques I found in a forum thread from 2010. The first technique, that cuts the road from the terrain, creates a metaball tube and then the ‘shatter’ option in the new Boolean Sop. To place the power-lines I'm lofting a point along the road curve and then just using Copy To Points.

So far, I think it's working pretty well. It can handle overlaps and pinching, and it's relatively easy to place objects along the road. There's currently a problem with the edges of the geometry. This can be fixed by extending the length of the spline off the edges of the geometry in some way, but for my purposes right now, that's a minor issue.
I'm kind of at a loss as to how to take this to the next step though, like separating the sidewalk into panels, or getting something approaching reasonable UV's onto the road geometry.
To people who have done this, where do I go next?