My two cents with respect to walking vs riding and scores. In my 20's when I was a hacker. We would usually get a cart, wouldnt ride it all the time but we were young and enjoying a couple of beers. We used to refer to the cart as a beer holder. Now that I am in my 40's and play the game more seriously, I walk because it gets the blood going. I think my scoring gets better due to the fact that I walk. If you are in a cart most of the round, you are not warming up and getting loose. If I am playing a course with mandatory carts, typically I let the other guy drive and I walk to my ball. I think walking would actually be a benefit over carts if you are in somewhat good health.
I was surprised to see that carting actually consumed that many calories vs walking, as I carry a little bit of weight up front, I was kinda hoping for a bigger spread in calories but will still walk the course, I need the exercise and really need to lower my front 9 scores, I am 4 shots worse on the front versus the back.