After another brief interruption due to a snowstorm, I dry sanded the doors and trunk lid. I discovered several small low spots, which I took care of with a bit of polyester finishing putty. Since there were several spots of putty, and I had also sanded all the way into the epoxy primer in a few places, I decided to give everything one more coat of filler-surfacer, thinned a bit so it would lay down extra-smooth.
Tomorrow I will wet-sand them, and the day after that I will hopefully be able to do the color coats. Fortunately they are predicting good, warm weather.