I also have a whole house fan at my primary residence, they are great. A couple of ideas…you could install one or more small whole house fans on the gable ends of your cabin. Also you could install a fan within a skylight that could be opened when you needed to ventilate. I have seen an opening cut in the ceiling, creating a flat surface on the roof, installing the fan with a cap. One thing for sure, not going to be as easy as installation with an attic.