A pic of the rig would help greatly, specially the area under discussion from several angles!
Howling or whistle would indicate air incursion or excursion. Rushing sounds all around would probably outside noise infiltrating from the wind etc. Load a sound meter application on your phone or buy a db meter and move it around the rig while someone else is driving or you are parked in a very very windy location and sniff out the noise source! Use extreme caution if you are untethered and moving around the unit while in motion! Or best is take it back to the manufacturer for a fix.
I get all my rigs undercoated and generally it reduces the noise level inside by a huge margin while also adding some sound proofing and insulation qualities.
RUSTIC is good.
Kudos to those who make Local, State & Federal Parks & Campgrounds possible and to those picking up the slack by Providing Private Campgrounds.