[kbs666]

If I was to ever to buy or download a rulebook for RW it would be purely to slice up and put the pieces I cared about into my existing articles and to merge stuff like feats and spells into my existing lists of such. I'd never maintain something as a book.

Custom categories make only a limited amount of sense if you use a lot of published material which all follows a single convention. Paizo, for instance, has been very consistent in how they describe settlements and other geographic locations. It would make little sense to deviate from the standard Pathfinder categories of you were using a lot of that material.