I always thought the line “drove my Chevvie to the levee but the levee was dry” was a reference to the murdered civil rights workers Goodman, Cheney, & Schwerner because their bodies were found in a levee.
And, “Them good ol’ boys drinking whiskey and rye” referred to the Klansmen who killed the three activists.
Could be. When my father was stationed in Mississippi he said that the counties which had levees were the only ones that WEREN’T dry.
Personally I think Starry, Starry Night is a better example of McLean’s talent. Not a word nor a syllable wasted there. A very fine piece of music.