As lostacrhitect said, don't paint it just to be painting it. Touch up whatever minor places are rusty. Worn paint is part if its heritage and the paint will be original only once. Of course it has already been painted over then paint all you want, and it is your bike after all. Understand however that making it look as good as new is quite difficult!
Sew-up tires feel different from clinchers. Some of us think that difference is worth the extra trouble. But a set of clincher wheels is not a bad idea too while you learn about sew-ups.