I think the issue lies with the amount of calories you need to hike, not the oil percent. People are looking at your hiking plans and see "thru-hiker" as the plan. But, you might fit a different mold. Thru-hikers generally are expending more energy than they can eat, because they are hiking long miles, and can only carry a limited amount. You will be carrying a limit amount, but maybe not hiking as long. We all don't really know how much energy you will need each day. That is for you to figure.

I think you will be good with 10% of calories from fat. I just would be worried that you get enough calories. If you are lean now, then you will notice sooner. If you are a little heavy, you won't notice for a while, which might be a good thing. Anyways, I would just plan to have a diet reassessment every so often to either change the amount of calories covered, or calorie binge for a few days (this could mean eating a lot more vegetables and whole wheat for a few days to calorie dump before heading out again). In other words, when you resupply, try being in a town where you can buy more food. If you feel like you are lower on energy, eat more quantity (same fat percentage) before loading up.

Moving on....thanks for the link to Ornish. I enjoyed it, and plan on using some of his ideas. Maybe not when weekend hiking, but definitely every other day.