Before the 30" rule, we built our cart to go through a 36" door. That means, bacuase of the door stops, your cart shouldn't be any wider than 34". Most building codes require at least a 36 inch door for safety reasons. Doors in Atlanta sometimes have a divider jamb between double doors, so getting through easily if you make it larger than 34 inches will be a problem. Make your cart accommodate the robot lengthwise for transporting, and can also hold the robot sideways in the pit, if that works better for you. Be certain you design in supports that will keep the robot off a platform, so you can test the systems while in the pit. We find that we have more room if we keep the robot lengthwise in the pit. Our cart has a scissors lift to change working height, drawers for tools, storage for extra batteries, and a work light that works off the 12VDC on-board battery supply. If you have been to Granite State, New Jersey, UTC or Chesapeake Regionals, you've probably seen it - it's bright yellow with a large smiley face.