consider renting a low psi sprayer, one that you can add additives to. Get a fan tip and add bleach to the system's pump and spray this on. Force with Bleach will also make this process faster.
You know, all the mold must die or it will come back and come back through the paint again. Do this procedure several times and let it dry thoroughly before painting.
This is not a good time for drying, ventilation, and sun to assist you. You might want to kill the mold first and consider painting in the Spring. I do not know the area of your residence and its climate.
BUT, the main concern is painting any surface that has underlying dampness.