A47 appears to be less than a mile away according to Google Maps scale bar. Walking to Great Yarmouth is listed as .1 mile (I don't know how though since I don't see any bridges across the water).
In addition, that's a stop along the train line to Great Yarmouth which isn't exactly nowhere. So, are they running a train only to Berney Arms? I doubt it terminates there. Now, it could be that passenger service is sparse because it follows the geographic feature (the river) rather than cutting through like the roads.
Finally, a lot of this stuff stems from the massive cuts that the railways took in the 1960's. That area used to have a lot more rail lines.
