Bet the railings that force passengers to walk in the road doesn't help
I've done the walk from the train station up the hill to the airport before. The serious lack of both pedestrian signs (the only signs seem to be car-centric and send you the long way round) doesn't help, nor do the location of the crash barriers.
Doing it in broad daylight with a small amount of hand luggage, the walk is just about do-able. If it's dark, raiining or you have luggage weighing more than a few kg, you can completely forget it