I don't know too much about Silent Hill, but my outfit situation that needs generous amount of ass-wuppin' is this: link
Naw but really. A black long coat like this: ( link ) or a peacoat, a red zip-collar sweater, a white button-up shirt with an oxford point collar, straight cut dark blue jeans, and black boots. Pretty much my uniform as an upperclassmen in college. You could substitute the color black with Navy blue in the coat and the black boots with brown ones or something.
If I were gearing up to head into Silent Hill, I'd want lots of pockets to store lots of things, so anything remotely military-esque. Definitely go with pea coats, cargo pants, militaria shirts (Converse makes some), maybe even trench coats, and preferably boots of some variety. Anything dark/drab is probably what you'll be looking for.