Well, DK if Fogerty's 'accent' is affected or natural, but it's not all that unusual for someone (like me) who has lived all over the place to end up with a real 'mongrelized' accent. When I spent a year in Texas in my teens, I probably came away with an accent that was a little bit central Texas, a little bit remnants of Newark, and a lot of central Illinois.    Then when I later spent 3 years in Toronto, I added more than traces of that to my speech patterns.
Why not Biloxi and Brooklyn?