Good advice so far. Massage those legs a bit after riding. I'm solo so I'm thinking of getting a piece of hard round foam for the back of my legs.

Get plenty of potassium and make sure that your pedals and cleats fit your posture as regards any possible toe-out or toe-in....(knees grinding ? )

I'm 11 years off until last spring and am going to cancel my century plans
myself until the end of the summer. Takes awhile to start from scratch again.

Reality hit the road.