My beloved 2001 Litespeed Tuscany and my 2014 Cannondale SuperSix EVO Hi-Mod Team bike
Welcome to BF.
1. Take your bikes. Can you imagine riding 100 miles on a bike that may or may not fit comfortably?
2. Don't rush thru the ride. Conserve your energy. Ride at a slightly lower speed than your usual ride. Don't pass any rest stops. Stop and relax while eating and drinking and refilling your bottles.
Since he's 60 (and I'm guessing you're over 50 also ) stop by the 50+ forum and say hello to the "old farts".
2009 Gianella custom steel cyclocross, 1983 Marinoni fixed gear, 198? department store beater for scootin' round town
Definetly bring your own bikes. Describe the type of century you are looking for; hilly, flat or combo, leaving from the city proper or wherever you are staying or are you willing to drive and leave from there?