Some of us who collect and ride vintage road bicycles have come to appreciate a bicycle's patina of age. Sure, it is just great to have a freshly painted steed and that is great if the frame chrome and components match the freshness. So, option one is to forget paint, touch up any bare metal on the frame with paint or nail polish and then ride the bike. If you wish, you can paint it anytime but first, it is wise to ride the bike and make sure that no frame work is required.
I painted this old Peugeot with Rustoleum and a paint brush, believe it or not...
And this old Legnano, though sorely in need of paint, has been with me for a long time. I have come to appreciate the appearance and it is not deteriorating in any way, as nearly as I can tell. I might paint it someday but not today...
