Winding road effect ... is there a better way?

[Contours]

For the umpteenth time, I find myself trying to illustrate a winding road going into the distance. Invariably, I look at the result and don't feel the curves and perceived depth are quite right. (It's a simplistic version of the uncanny valley phenomenon.) And all the while, I know it's just geometry, which the computer should be able to solve.

Here are examples of the kind of "scene" I'm working on: http://www.123rf.com/stock-photo/winding_road.html
(And, yes, I've tried tracing. The problem, there, is finding the right traceable roadway.)

I've attached a method I've used for lines going straight into the distance. But nothing I've tried can give me the "to the right" ones I'm after. And, of course, I'd like to produce both edges of the roadway in a single operation.

Is there a better way with Xara?

Thanks in advance for any suggestions.