I think his happiest years may have been in 67 and 68 with the Cardinals. no pressure, two World Seires appearances, his best World Series performance (67), and a friendship with Augie Bush that resulted in a Budweiser distributorship in Florida on retirement.
There was a nasty feud between AB and the Maris family after his death over that distributorship, but it ended amicably in a settlement.
One of my favorite card combos are his 67 Topps cards as both a Cardianal and Yankee.... no smile but I think because he thought he was going to be a Yankee again when the photo was talken
I did see him play as a Yankee while attending my first World Series in 1964 in St Louis...along with Mantle, Ford, and Berra. Musial had retired in 1963 but fortunately the Cards had Gibson in his prime.