RB I'm 70+ now, try to get in 300 - 400 miles each month as well. Many of those are on my trainer in the basement, in that where I live I'm not inclined to ride outside when it's raining or blowing over 20 mph or below maybe 50°F. Still, it's all exercise I wouldn't get otherwise, and an escape from the more mundane pursuits of daily life.

In that I still work (retail hardware store) ~ 30 hours a week I consider myself 're-treaded', 'retirement' not being an attractive proposition just yet.