Mobile scaffolding units include a vehicle for movement across ground surface, a stationary platform rigidly fixed to the vehicle at a predetermined immovable height above the ground surface, and a gantry platform operatively connected to the stationary platform for movements between a retracted position where the gantry platform is nested adjacent to the stationary platform, and an extended position wherein the gantry platform extends laterally outwardly from one or another lateral side of the stationary platform to provide an operator on the gantry platform an extended horizontal reach laterally of the vehicle. The mobile scaffolding units allow an operator to work at elevated heights and with lateral reach in one area of a work zone (e.g., to trim roadside vegetation) and then move to another area of the work zone without requiring an operator to dismount from the gantry platform.