Wildflower Century training

OK, doctor says that I can't run anymore. At 60 I came up with some osteoarthritis in my left knee. Probably related to a 40 year old surgery on that knee. Guess I never will run that marathon I have been putting off for about 30 years. Regardless, doc seems to think that pounding the pavement with 180 lbs centered directly over that knee may not be the best idea. Said something about an eventual knee replacement, sounds expensive, painful and basically undesirable. He did say that I could do other kinds of exercise - swimming, walking, cycling, anything that doesn't have the high degree of impact associated with running. Since I have already been doing spinning classes at the gym anyway, I got my wife to buy me a road bike for Christmas and decided I was going to do a 'century', a 100 mile bike race. That is roughly the equivalent, I hope, of running a 26.2 mile marathon. So I signed up for the Wildflower Century in San Luis Obispo County California in April of this year. I have been Spinning for 4-1/2 years and am doing 2-4 classes a week. My longest road bike ride thus far has been 32 miles, so I need to get off my duff and get in some longer rides. Stay tuned