Meet the Super Mega Bot: a modular rugged robotic platform that can tow heavy objects, including a Ford F-250 Super Duty truck. It weighs 225 lbs and tows vehicles up to 6500 lbs. You can use cameras and other modules to do more with the robot.
The robot has a max speed of 15 MPH and can climb slopes up to 35 degrees. A water resistant upgrade is available for it. More info can be found here.