Great report. It sounds like you need a lot more caloric intake per day and more per hour. When you are climbing at higher power levels, you will use a lot more muscle glycogen / glucose than fat. If I were doing that ride, I would take in 200 - 400 calories per hour on the bike in the form of gels or some type of high carb drink. I would eat lighter for lunch and then eat everything in site for dinner and have a high carb breakfast.