Work platform systems and related methods of assembly and use are disclosed herein. In one exemplary embodiment, a method of installing a work platform system into an internal cavity of a structure includes supporting a first platform portion at a first location, and adding a plurality of additional platform portions to the first platform portion, where successive ones of the additional platform portions are respectively positioned at respective locations that are successively farther outward away from the first platform portion. The method further includes coupling the additional platform portions to one or more other locations, and detaching the additional platform portions from one another. The method additionally includes lowering or raising one or more of the first and additional platform portions to one or more additional levels below or above the first level, where the work platform system includes the first and additional platform portions.