Yeah, I agree. I wasn't going to say anything because the question was "Can I carry a step ladder on my coach ladder". The answer is, sure. The next question is "should I carry a step ladder on my coach ladder". The answer to that one IMHO is "no way". I have seen many coaches going down the road with ladders of various sizes and shapes strapped to the back. To me it always looks like the Beverly Hillbillies going down the road. It really kills the appearance of many nice looking rigs. I purposly purchased a 5' folding double sided ladder that would fit in my storage bays. A little more expensive, but it's not strapped on the outside of the rig.
I'll shut up now! Just my .02