Also, it doesn't take much to start a vintage or C&V ride, just pick a good regular date and time, and get it advertised in CL, Bike Forums, Classic Rendezvous or whatever social media you can muster. May start slow at first but there's enough of old and new riders who would probably enjoy a nice ride without speed pressure.
A good route reasonably free of traffic at the time you're riding, and a liberal interpretation of what bikes to allow is helpful. Its all about the fun of riding, and no one should be turned away for the bike they are riding.