I've heard of using a portable closet as a film drying rack. So I'm wondering, how about taking a black garment bag, the kind that's used for suits, and using that to hang the film to dry once you've rinsed off the antihalation layer? Of course, once you hang the film in the garment bag, you'd have to seal off the hanger slot and any other places light could leak in. I'd also worry about the wet film sticking to the inside of the bag, but maybe using an extra thick hanger and weighting the end of the film would help.