A personal watercraft or alternative motorized vehicle including a superstructure characterized by a unitary seat and hood assembly, which incorporates an integral steering mechanism therein. By providing a unitary seat and hood assembly, and integrating the steering mechanism therein, the height of the deck assembly, at which point it is in juxtaposed relationship with the seat and hood assembly can be substantially lower than in prior art devices. This design allows for raising of the unitary hood and seat assembly about a single pivot point, thereby providing an interface of juxtaposition which defines an extended singular engine compartment opening that enables unfettered access to the entire engine compartment. This extended singular engine compartment opening is of sufficient size and breadth to permit removal of the entire engine assembly.