Howdy Kathy
It was nice to meet you

Thanks for your compliment but I'm not that much faster (usually just under six hours). You've decreased your time to Long Valley by an hour in only four trips -- that's a tremendous improvement.
As you pointed out, the key is to find a pace that you can comfortably sustain over a long period of time.
Your hard hikes for two weekends before Skyline could have contributed to your fatigue level. While I'm a big proponent of how nutrition can help performance before, during, and after exercise, nutrition can't do everything. When muscle fibers are damaged from hard hikes or runs (soreness = muscle damage), they don't store muscle glycogen as well. The contractile properties of the muscle are also negatively affected by muscle damage from hard hikes. Even when muscle glycogen restoration is back to normal, this does not ensure normal muscle function.
One other consideration -- how is your iron status? Iron deficiency is fairly common in women. Iron status should be checked by serum ferritin (storage iron) and serum transferrin (transport iron) in addition to serum hemoglobin.
I'm happy to assist with advice on nutrition before, during, and after hiking as well.
Miles of smiles,
Ellen