My daughter and I just finished Part 2 of the Mt. Rainier Grand Tour, a tough cross country jaunt that cuts off from the Northern Loop Trail and travels through the Elysian Fields and Moraine Park, reintersecting the trail on the south side. I had to throttle back as my daughter was on her first real hike of the season, but I felt really strong throughout the hike, even those final miles approaching an 18 hour day at the end. I never red lined on the climbs, never found myself panting to take in more air, and mechanically had no problems. This hike felt like ones I did in my 40s, a tough day but far from a sufferfest. Although I felt tired the following day (after arriving home at 4 AM), my muscles were not sore.
I feel like the body is dialed in (although I'm still carrying about 7-10 extra pounds), my equipment is dialed in, and I'm ready to launch with confidence on further adventures in celebration of turning 60, 'cause it sure doesn't feel like it!