Paint Experts: Process Advice Needed

I don't think I'd worry too much about a little bare metal in Sacramento as long as you will have paint on it by November when the rainy season starts. I've been working on the roof sub structure on my car and am grinding/brushing all the rust off the untreated and unpainted surfaces. It's been sitting for a couple months with no protection and there's no sign of any corrosion or reaction on those areas. Now if there is uncovered bondo, that may be a different concern to get something on it.