There are no guarantees, in my opinion, as to finding this, and whilst GPS units have fastest and shortest options, they are generally far from being the most interesting. I have a couple of things I look for on the map when planning a route to a new location where I want the journey to be as enjoyable as possible. In short, water and hills are the clues. Rivers, by nature, meander their way from point A to point B, and throughout history man has used them as a guide for ease of mobility. Pretty obvious when you think about it, as they tend to be comparatively flat over a large proportion of their length. As a development of this, there are very often some nice roads that will follow the course of a piece of water, often mimicking the water’s twists and curves. This is not full proof, of course, as very often, especially close to large towns, newer roads are built to be as straight as possible, but this can be a good source of interesting tarmac. Similarly, hills are often a good source as the roads over them tend to twist and turn in a ribbon of pavement.