I'm sad about the passing of a musical icon as well. I knew almost all of Peter, Paul and Mary's songs. Their song, "Leaving On A Jet Plane" became "our" song in 1969 because my then-fiance and I were living in different cities.
We saw PP&M perform almost every year here at Wolf Trap, outside Washington, DC. They were supposed to perform on August 22, but an announcement was emailed to ticket holders (including me) that Mary was too ill to perform, but Peter and Paul would still be performing a tribute concert to her and their music. I ended up not going because of another commitment, and I would imagine as good as the men are, it just wasn't the same without Mary.