GL I would add from further reading the blog that maybe you need to look at diet/power.
Simple approach carbo = fuel Protien = repair. I use salt sandwhiches as my great treat on long distance 🙂 I also have one type of fuel bar which I always eat on all races. I also train with same fuel intake so my body knows what to expect.
On long enduro rides water, fuel intake is difficult so you have manage effort and fuel intake carefully. Take in more plain water. This means backing off the power a bit to allow your body to continue to take in energy. It tends to slow down as you increase effort etc.
I dont see any mention of gym etc some cross training is great at maintaining your endurance on long distance or multi day events. Your arms, back etc dont become so fatigued and eat up valuable energy.
Its all a energy game 🙂