I paint alot of fleet trucks and I think your idea is very good, do a good prep job, and use the summit primer and paint. I would prime the complete car using the primer as a sealer and surfacer. You said you havent painted in a few years so if you dont have one, I would go but a cheap gravity feed gun from Lowes or H.F. I use these when I dont want to use my "good" guns and they actully work very well and the newer paints dont do so well in the older siphon guns.
