Just a few things I would add.
Some bagels or hard rolls for your sandwiches with the cheese and summer sausage, they don't get as mashed or broken like bread or crackers.
Sometimes bring some Stove Top stuffing and a small can of chicken or beef. Cook the stove top and dump the meat in.
Quinoa is great taste wise, nutritionally, and very light. Cooked by itself it tastes a little nutty and maybe a mild popcorn flavor. But I add meat to it. Great protein to carb ratio.
Powdered Gatorade and Emergen-C, especially if you sweat a lot.
I guess I should get some of that Via stuff, although it sounds spendy. Lately I've been taking Medaglia D'oro instant espresso and add more water than it calls for. Pretty stout taste that's not for everybody. You can get it in grocery stores. I used to bring ground beans, and a small Melita coffee filter. It's a plastic funnel you set over your cup or pot, put a paper filter in, and pour boiling water into. They come in diff sizes and weigh next to nothing.
And last and I almost hate to admit it but sometimes I bring some Pop Tarts !