I wish you well on your trek! Certainly, come back and share your experience, as it seems we all have a difference of opinion on how to accomplish a task like that!
Since I am not "athletically inclined", I am sure I would not be able to do a trek on the same scale as you are planning, but I would like to do a backpacking trip at some point in the near future. So, any suggestions from your experience would be very much welcome.
The foiled tuna idea is great! I normally pack those on my camping trips. When I go camping, it isn't a cush-cush trip. And, since space is very limited, I don't like hauling my kitchen pantry along. Plus, I don't like having to run to a grocery store to stock up on veggies. So, my carb staples are generally a bit more on the "higher-glycemic" side, things that are not going to require refrig and are easy to pack. Although, I imagine that taking apples along is probably going to increase the weight in your pack.
I have not had any significant problems staying in the Zone when I am camping. I don't have spells of hypoglycemia, I don't have early hunger, etc.