There's no way this title doesn't go to someone course bagging in Illinois! They should change the state's nickname to "Nine Hole Wonderland."
Most new courses I've played in a day was 4 when I visited Lemon Lake. Now that I think of it, while I have played 4 courses in a day on several ocaissions, I don't think I've ever played more than 4 courses in a day, whether new to me or previously played.
Don't think I'm likely to play more than 4 new courses in a day anytime soon (if at all). When I go on the road, I definitely "cherry pick." Given that I make a conscious choice to play the best in an area, chances are they're pretty challenging, and take some time to play (or at least to appreciate) so I'm not really able (or willing) to rush through them. Factor in drive time to/from and possibly between... I think four's about my practical limit given my self-imposed constraints.