I actually find it surprising that with your age & as many days as you're off the bike that you are sore a lot. Are you on your feet or otherwise running around on your days off?

I actually start all my rides with a 20 min warm up & a 10 min cool down. As [MENTION=158672]FBinNY[/MENTION] mentioned, I mix up easy & hard days but I'm usually on the bike 5-6 days per week, so I don't get as much rest as you.

You say your nutrition is good and I'm not sure exactly what that means to you. However after every hard ride, I consume carbs + protein to aid recovery and set myself up to build muscle- if you're riding hard & not doing that, you might give it a try. You need good nutrition all-around for sure but the post-ride recovery drink is particularly important for me. My drink of choice is Greek yogurt, berries, a little sugar, skim milk, and ice cubes, whirled in the blender. I aim for 25-30 gm protein post ride and the yogurt & milk have a good bit of carb/sugar.

You also should be sure to schedule a light week every 3rd or 4th week.