Step adapters for a rung ladder to provide an increased support surface or area is described. In one embodiment, the step adapter includes a brace, a platform, a lock and a safety bar. The lock, safety bar and platform are provided to structurally engage or embrace a rung of a ladder, and the brace supports the adapter against the rails of a ladder so that in total the step adapter provides an extended step structure to ease standing on the ladder, especially for an extended period of time. In another embodiment, the step adapter includes brace, platform and lock sections, where the platform section side edges are configured to lock the step adapter in place on a rung of a ladder. A tray overlay is also described which when used in combination with the step adapter (which serves as a support) provides a service area for holding work-related items.