I (32, not in good shape at all) started biking last year for the first time in years and was able to do 60 miles (100km) my second time out. with hills. It's about 5 hours at a very slow pace, but we did it in 3 1/2. My father (72) rides regularly with a large group of older bikers and does 150km twice a season, but 80-100km every weekend. My mother-in-law (60) recently got back from her second cross-country bike tour where she did 130km 6 days a week for a month.