A planning tool plans movement of a boring tool for an underground drilling operation. The planning tool includes one or more wheels for rolling on a surface of the ground along a path responsive to movement by an operator to characterize the surface contour and to generate guidance for the boring tool to reach a target position. Surface roughness is measured based on instantaneous rate of change of an accelerometer output. Accelerometer cross axis sensitivity compensation provides for more accurate surface contour characterization for paths that are not smooth. Accuracy of rolling datasets is predicted and associated indications are presented based on surface roughness in combination with speed. A rumble/speed gauge guides operator movement based on detected surface roughness in combination with speed.