A box with a wheel assembly platform has a tow strap with a folded position stowed in a recess in the platform and an unfolded position accessible outside the box. In one embodiment, the strap is incorporated in a pre-assembled handle pack positioned in the recess. The strap may be retracted by a torsion spring, and may be coiled in the pack by use of a rotating fork. In one embodiment axles projecting from rollers are supported in recesses formed in the platform, and in another embodiment the axles are supported in notches in the bottom end of cylinders mounted in cutouts in the platform. In a further embodiment a box has hand holes in opposite walls with a spacer panel providing finger access behind the holes. The platform may have hinged panels. A thermoformed skin may be applied to the platform or constitute the platform.