You are going to have that "New Camper Smell" for a while, no matter what you do. We keep ours in a fenced in area/barn type structure with a raised cover over it. We leave a vent open (Maxx Air cover over it) and leave an air freshner open. No issue leaving bedding and towels in the camper. No smell issues. What you don't want to do is leave any food stuff that are not very well sealed. We remove all our cooking spices, becuase even in the mfgs continer, they will not seal good enough to keep out the moisture. Otherwise we have not had any issues since we started camping in 2002.
Even if you think you got the bed ends good and dry, check them a couple of days after your trip, just to be sure. I try to make a habit of doing a quick check every week or so to make sure there are not any suprises. We try and use our camper at least once a month.
Chuck Roder & Family
'07 Surveyor SV-235RS & '03 Chevy TrailBlazer EXT LT V8
High Springs, FL.