I live down just south of Portland, and I do use Bondo and paint year-round. You need a hot box. Basically, a rubbermaid tote with a heat lamp inside (pet store find). Actually, pretty much, you need to make a fake Easy Bake Oven. It will keep the fumes contained and keep it warm enough for the bondo to cure.
Also, you might need to build a painting booth (something you can bondo in with it blowing the fumes outside). Doesn't have to be much. Mine is a table with an acrylic shield on the front and a couple of sintra sheets for sides. It has some plastic strips on the lower front that I can put my hands through to do the work I need without exposing too much for the fumes to get out more than necessary. It is also good to sand in to keep the particulates from going everywhere. Just make sure to clean it regularly or the acrylic shield can get scummy. It is built against a window and has a small fan to suck out the fumes. It also has a couple of heat lamps to keep it from getting too cold inside.