A cushion set for use with a seat having a seat back with an upper portion and a lower portion includes an upper back cushion and a lower back cushion each having a forward surface and an opposing aft surface, each forward surface including at least one back cushion forward attachment device, and each aft surface including at least one back cushion aft attachment device; and an inflatable lumbar support having an aft surface that includes at least one lumbar support attachment device. The aft surface of the upper back cushion is attachable to the upper portion of the seat back, via the at least one back cushion aft attachment device of the upper back cushion. The aft surface of the lower back cushion is attachable to the lower portion of the seat back, via the at least one back cushion aft attachment device of the lower back cushion.