I don't have a bumper pull and have a lot of unused room up in my forward storage under the pin box so maybe not helpful but I would avoid tacking a ladder onto the back of my camper even if there are stickers indicating you can do this. I would purchase a telescoping extension ladder (probably 12.5'). as they are far sturdier and secure than using the one I have on my camper. I store mine in that forward compartment.
https://www.amazon.com/Telescoping-E...4507641&sr=8-6
You can purchase a Stromberg Carlson ladder and screw it onto your camper if you want this type. They are pretty much like the OEM. Problem is, the attachment points are not very numerous and you may not be hitting something solid every time you put one the screws in. In addition, you will be making more penetration; especially on the roof. It can be done but you will have to make sure everything is sealed properly. Note the directions say all the screws must be fastened to the camper's sub frame or backing. I don't think a penetration into filon would be ideal if you didn't hit the frame when attaching fasteners.
https://www.amazon.com/Stromberg-Car...4507762&sr=8-5