A mountable elevator system includes one or more horizontal bearing frames and one or more vertical frames, each vertical frame being connected to one of the horizontal bearing frames. One or more step stringers extend between the one or more horizontal bearing frames and the one or more vertical frames. A multi-piece platform includes multiple step pieces mounted on the one or more step stringers. The cabling is configured to extend and retract the multi-piece platform. One or more step support locking structures can be configured to secure a top step piece of the multi-piece platform, wherein the multiple step pieces of the multi-piece platform separate into multiple vertical levels as the multi-piece platform extends. The multi-piece platform is configured to raise and lower relative to an entry door of a vehicle.
