We have the reflectix backed pillows that go into the ceiling vents to keep the heat out. Do you store you RV with the pillows still in place when storage is outside in full sun? Would there be too ...
They block noise as well as insulate during colder temps. I would use them in the winter as an insulator while leaving one vent partially open to vent inside air to lower the chance of condensation. While in storage or parked in my driveway, I open all vents with covers to allow air to exchange because i'm not concerned about what temp it is inside the rv.