In the pursuit of Jessica Simpson and her kidnappers,
Holmes and Russell travel north from Cardiff and then west "into the hilly greensward
that curled up toward the Brecon Beacons."
A day more, and then on the third day they passed the Simpson's camping place. Further
north then again, so it's not certain where into the hinterland of Wales they have
ventured.
It might be noted that Ms. King uses current terms for counties in Wales, and
according to my encyclopedia, 1974 saw a major change in Welsh county names.