A lot depends on your age, current fitness level and current mileage. The sages say that you should increase your distance by no more than 10% each week.

It's also said that if you can do 80% of your mileage by the time the big ride comes along - adrenalin will carry you for the remaining 20%.

I echo the advice - during the ride eat before you are hungry & drink before you are thirsty. This is a good time to experiment with different foods to see what works best for you. Some people like energy bars, some like bananas & other "real food" - it all depends on what works for you.

Be sure to refuel within 30 minutes to 2 hours after a hard training ride. That is when your muscles can readily accept glucose. You can supplement with l-glutamine - 5 grams - after a ride and that is supposed to help muscle repair. Be sure to refuel with fast acting carbs and some protein.