Meet the HK1000-V2 Robot from SuperDroid Robots: a heavy duty 4WD robot with 200lbs weight capacity that can take on rough terrain. It uses heavy-duty motors and 13-inch tiller tires. This robot measures 26 inches wide and can fit between most standard doors. It has max speed of 3 mph.
This robot is ready for off-road conditions. It has multiple attachment points. You can find out more about it here.