Century training
Denise,
What a fabulous goal! I don't know how much a week you currently ride, but I would say that you should work your way up the same way runners do. Runners are told to increase the distance by about 10% a week, and that's what I saw for riding as well. If I were you, I would train similarly to what I did for running a marathon. I would do two easy rides about 40-45 min each (at the beginning and working up to an hour as you progress); one shorter, faster ride that covers about the same distance (or a little more); and one long ride. I'd say to work the distance of the long ride up from 15 or 20 at the beginning to about 75 miles at least 2-3 weeks before the actual 100-mile ride. Taper off the last week or two so your legs are fresh, and I'm sure you'll have a great ride.
Linn