Another GoogleEarth imagery trick I forgot mention is to check where the path is supposed to cross field boundaries. There is often a wear mark by gates or stiles. By the way Mel - they aren't satellite images; they are aerial photographs.
I think I tried to draw members attention to this 5 or more years ago.
The reason for this is compaction by the tractor wheels, when the seed bed is being prepared for a crop, thus the pattern of the preparation the crop can be seen on an areal photo taken in the early summer period when the skies seem to be clear enough to get the full area for patching together an areal map.
When the cultivations are finished the machinery heads back to the gate for the return to the main farm holding or assembly point.
As a by product of this observation it should be possible to work out which holdings or previous farm type buildings are no longer part of the agricultural system.
May give you a clue when you can safely take a liberty with the righteous way network and improve a route.