I was looking at a nice little enclosed trailer today. But it was only 6' wide, which is fine for me. However, the door opening looked small. On an open trailer you have a full 6' but on enclosed you do not. That's something I hadn't really thought about. So what is the average door width? Or the average setbacks for the box corners? I'm concerned how wide I'll have to go to fit a 60" mower.