Provided is an accessory for a self-balancing board having two lateral foot-deck ends, each being coupled to a motor that drives a wheel in response to its orientation. The foot-deck has at least one sensor that is triggered when a rider is in a riding position thereon. The accessory includes a chassis, at least one travel surface-contacting element, a seat, and an engagement structure that releasably engages the self-balancing board. At least one sensor-triggering element is actuatable between an idle position and a triggering position, wherein the at least one sensor-triggering element triggers the at least one sensor. At least one control member actuates at least one of the engagement structure and the at least one sensor-triggering element to control the orientation of the lateral foot-deck ends. At least one manually actuatable actuator actuates the at least one sensor-triggering element between the idle position and the triggering position.