I totally agree with you - I have always thought that the romans just imporoved and adapted the trackway system that was already there. We are still carrying on this process now - if we build a motorway (say, the A1M at the devils arrows) than we follow the existing route, but build bigger.
And if you were building a monument, then you'd build it where people would see it, from the road. I've just been looking at the map for penmaenmawr - burial chambers, standing stones, circles - all next to an old trackway from the axe factory. This trackway then became a roman road, with a roman fort below it.
sam