When asked how he pitched into his late 30s, he attributed it to "clean livin' and the spitball." I'm guessing that's what got him into his 90s as well.
I don't know much about Preacher Roe, but this quote from Casey Stengel about Roe and Eddie Lopat makes me think I would have liked him quite a bit:
"Them two fellas certainly make baseball look like a simple game, don't they?
Makes you wonder. You pay all that big money to great big fellas with a lot of muscles and straight stomachs who go up there an' start swinging, and they give 'em a little o' this and a little o' that and swindle 'em."