The mechanical behavior of a military vehicle during off-highway operation is complex and highly nonlinear. Some current vehicle concepts include added intelligence through the implementation of sensors and controllers to enable autonomous or semi-autonomous operations. Control systems have typically been developed with controls software where the mechanical plant and sensors are represented as simplified and often linearized blocks, resulting in a poor vehicle assessment. This paper describes the development of an integrated environment for a control system, mechanical system dynamics, and sensor simulation for an improved assessment of the vehicle system performance. The vehicle chosen is an autonomous robot that attempts to follow a prescribed path along an off-highway terrain. The effect of including a stability controller for vehicle mobility is assessed. The architecture of the integrated simulation environment is described and its potential to improve schedule and reduce risk of the development of mechatronic military vehicle systems is explored.