Cupboards, Closets and Cabinets
Anyone who has ever pulled down an inhabited bowl or pan or found an unwanted treat in a cereal box knows that cockroaches are wont to roam throughout every inch of kitchen cabinets. They also cavort in closets and lay eggs in linen closets.
In particular, cockroaches like upper inside corners of cupboards and cabinets and hang upside-down there. Keeping all food in tightly-sealed containers is necessary if bugs of any kind are an issue, and not just for the squeamish factor, but also because roaches may carry food poisoning and other bacteria.
Thin dustings of boric acid-based powders and well-placed traps may help with areas where clothing and linens are stored, as well as in bathroom medicine cabinets and behind them.