I think that's a good strategy, as for primer to use over that I'd use an epoxy. If you already know what brand of paint you're using (PPG, DuPont, Omni, HoK, etc) then try to use that particular brand of epoxy primer. The nice thing about epoxy is that you can let the car sit until you're ready to work on it with the fear of it rusting through the primer. I saw a '67 fastback in a bodyshop a few months ago and they stripped it to bare metal, did some filler work and then let the car sit for a few weeks. When I saw it, the body was coated with surface rust and the rust was even under the filler. That means they get to either re-do the whole thing, or try to hide it from the owner by simply shooting epoxy over it, which is a 100% gauranteed failure. But if you shoot epoxy over filler or bare steel or a 2K primer like you're considering as soon as possible, you'll be fine.