This morning I did a very quck measurement:
front: the bumper mounts on the end of the frame horn and has a piece that goes down the outside of the frame rail. That is ~ 35" wide. The front is about 75" wide on the inside of the bends.
rear: the bumper is about 69" wide on the inside of the bends, and the mounts are 39" apart. I didn't have a chance to pull the wag out, so I couldn't get as good of pics for the rear.