I read journalist Mark Johnson’s Changing Trains the other day. It’s a semi-automatographical novel of a gay man at 19 and later in his fifties. He tells it from the alternating perspectives of his 50-something-year-old self being pampered on the TVG, and his 19-year-old self Interrailing around Europe for the first time.
While he doesn’t write with obvious humor about aging, the comedy does tend to leak out between the lines.
Given your own experience, I think you’d quite like it.