found mold growing inside my camper top, Cleaned all inside with mold prevent er . Any suggestions to prevent return.?
I'm going to leave the back slider open a hair for ventilation .
Also going to spray down top looking for leaks.

 

Mold spores are in the air so hard to stop it

But mold does need damp surfaces to grow.

You can get bags or tubs of moisture absorbers, like the desiccant packs you find in electronic product boxes.
You would keep window closed for that

Warmer air can hold more moisture than colder air
This is why the outside of a Cold Beer Glass gets wet on a warm day, the warmer air on the outside of the glass cools down when it comes into contact with the cold glass and leaves its water/moisture behind

Same thing also happens on the inside of the windshield on a cold day, and why we need Defrosters, cab air is sightly warmer, so deposits it's moisture on the cold glass

And the same thing happens in a camper, slightly warmer air on the inside deposits its moisture on any colder surface.
So you can insulate with moisture barrier, or lower humidity in the camper so no moisture to deposit on colder surfaces

Opening the window is about keeping same temp and humidity inside and out, not sure slightly open will do that