You mentioned the Back Porch Majority--
There's a CD available at Amazon, "Best of Back Porch Majority," which has a song titled, "Riverboat Days." Unfortunately, it is NOT one of the songs that has an available sound clip! Might be worth checking out, though...

You may wonder why I'm still looking for this--well, once I read your request, I was sure I remembered the song, too! I can't help thinking that it was a Disney thing, but I'm not finding any leads there.

Denise:^)