Yes you can shrinkwrap a camper/5th wheel.
They make mini vents to place anywhere on the wrap to help stop mildew.
You can also have a zippered door taped on to give you access all year round to work on your unit to get it ready for next summer trips.
The shrinkwrap works the same as a conventenional cover but cheaperin cost.
The only drawback is that the cover cant be used again once you remove it.
You can reuse the door and vents but thats it.