Just turned 61 and I got and followed Joe Friel's Training Bible at 41 years old. (I think his Bible has some details/training advice that is not covered in the 50 books. At 45, I got a copy of Cycling Past 50, and then got Fast after 50 when it came out. Good Stuff. Your cardio vascular system will adapt to whatever situation you regularly put it in as will your legs. When work didn't allow regular riding (5 days/wk) and I didn't have lights for dark:30 riding, I got rollers. You could get a second hand trainer to get in more frequent rides. I've never used a power meter because of cost and I have several bikes that I ride regularly. Keep your core strong--cycling as we do is hard on the back. I do 10 minutes of Dead Bugs with 5 lb. weights and a bunch of back extensions on an excercise ball at least three times a week for my core. I ride with a faster-than-me group some Saturdays and they all use a compact and a 28-32. They convinced me to move up so I got a 28 that I use when I ride with them. My other rides are using vintage 42-24 or 39/23. Every ride is a training ride. Recovery rides are training rides. Ride lots
