A U-shaped support frame has a base beam and parallel side beams extending rearward from the base beam and defining an open implement area, which can be made adjustable. A hitch is attached to the front end of the support frame and frame wheels support the side beams, and rotate about a horizontal frame wheel axis that is fixed in an orientation perpendicular to the operating travel direction. Implements are configured to perform an implement operation and to rest on the ground surface when in an idle position. The support frame is moved rearward to a loading position where each implement is movable to an operating position supported by the support frame. Each implement provides a beam lock connection between the side beams that resists twisting movement of the side beams to maintain the frame wheels and the side beams in a substantially fixed relationship with respect to each other.