Trailer Queen Of A Different Sort: What Is It?

In a recent CC foray that involves old large trucks, a kindly person on the premises suggested I look into a particular trailer that was being used to store some of the older items. I did, but didn’t climb in and take a closer look. And I don’t pretend to be intimate with the really old iron, except for some obvious ones. I do have a hunch, though, but I have a very compelling CC to put up, so maybe some of you might want to spend the time tracking it down, unless you know already. A cropped shot follows.