A trailer-mounted platform that unfolds to provide a multipurpose platform is herein disclosed, comprising a conventional double axle trailer. A pair of side panels is attached to a longitudinal edge and folded up for transport. In their folded state, the side panels form a triangular shape with a bottom center panel. As such, the interior of the triangular space is used to transport various items associated with the final use of the platform. Upon arrival at its destination, the side panels are lowered and supported with adjustable jack stands along with the center panel to form a platform assembly. The jack stands are adjustable over a wide range to accommodate ground conditions.