A portable payload carrier (e.g., military transit case) comprises a housing for supporting at least one payload therein, and a ground transport assembly coupled to the housing comprising a first transport unit (e.g., cover) in support of a wheel assembly. The wheel assembly can comprise a wheel and at least one wheel support structure configured to support the wheel about the first transport unit. The wheel assembly can be operable between a stowed configuration and a deployed configuration for transporting the portable payload carrier about a ground surface via the wheel by a user. A handle transport assembly can be coupled to an opposing side of the housing, and can include a deployable handle assembly for lifting and moving the portable payload carrier. The wheel and handle assemblies can be collapsible to maintain a form factor of the portable payload carrier when in the stowed configuration.