The "hole" the the camper roof for the luggage storage is nasty for both aerodynamics and noise. So, I got some foam insulation and made a fix. The unit will be held off the floor by some easily compressible foam pads, and the sides will be painted to keep the styrofoam from breaking up. A few strips will be added below to prevent vibration which would also cause the foam to crack. A sheet was $10.85 at Lowes. It will be attached securely to the roof with nylon webbing.
Styrofoam insulation with silver foil on one side
I cut it curved in the front and a slight taper on each side as the front width is about 2" less.
Placed on the roof
It's level with the sides. Will attach it securely with nylon webbing.