I'm doing my first century--at least I hope so--this weekend so I'll be interested to see what everyone says on this one. My "gut" (no pun intended) reaction to what you ate/drank is that I would have added some pre-ride hydration. I also would have eaten more about 2-3 hours before the ride and a little less (like just the banana) right before the ride.
I also would have eaten my first snack earlier than mile 50. I usually eat my first snack on long rides at mile 30 or so, i.e., right before I can expect to deplete my glycogen stores, and again at mile 50 or so. I would have made sure that I ate something salty during the ride to aid in digestion and to replace electrolytes (I also drink CytoMax energy during rides). I'm not sure how much water you drank after mile 50, but I would add that to the list because the Gu without water is hard to digest. Finally, assuming that I'm not feeling sick to my stomach by then, I would have had another snack at mile 70 or so and relied on the Gu only for the last bit of the ride. Finally, I would drink a recovery drink, i.e., a balance of carbs and protein, immediately after the ride, along with water and a carby snack about an hour later, before eating a more complete dinner.
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher