If you were able to knock a hole in the door, you could just do it where the latch is attached, and knock the whole latch off the door, but you'd need something like a sledge hammer, axe, or saw. I don't think you could even do much with a pry bar.
If you're talking about just making a small hole and putting some wire or something through, even that's unlikely, but if you somehow managed, you'd have to find and lift the stopper out of the way, and lift the latch at the same time. The swing of the handle is 180 degrees, and about a foot in distance, and even with a brand new trailer it would require probably about 10 pounds of pressure to lift. And that's with a roll up door. A swinging door would be virtually impossible to open without making a hole big enough to fit your arm through.
Roll up door
Swinging door