Power inverters are compact so you can power small electrics like a stick blender. Useful for hummus from canned garbanzos. Or white beans with garlic, rosemary and olive oil. Pitas are good bread to travel with as they resist the smashing and distortion that happens. Also good for the various "salad stuffings" of tuna, chicken, egg. The foil pouch seafood is of generally higher quality than canned but more expensive. It works well in this application.
Fruited yogurt and granola makes a simple muesli that I enjoy.
Bagels, cream cheese and various toppers. smoked salmon, canadian bacon and so on.
Dried fruit.
If you want to get out of the box further, Dian Thomas' series of books Roughing it Easy includes cooking on your car's exhaust manifold (tin foil dinner type things). One of them includes heating a rock in an oven for an hour or two (careful rock selection is important), then carefully loading that into a chicken cavity, wrapping in foil, then many layers of newspaper. There is enough residual heat to cook the chicken from the hot rock.
Frozen burritos. Let them thaw in your cooler, then heat on the dash in the sun while you're in a store or shopping or whatever. A black pocket of paper or fabric will help it along. I picked this one up reading 127 hours by Aaron Ralston. He got stuck in that canyon with half of a (thawed) frozen burrito. But it's a pretty good idea actually.
There are shelf stable pre-cooked rice packets in the grocers now. Some flavored, some not--all a little high on sodium if you're watching that. But they're useful for making a quick rice salad. Some olive, artichokes, grape tomatoes, green onion, maybe a little garlic, some fresh herbs or a little bottled salad dressing. Maybe load up at a salad bar with the additions and dressing then mix with the rice packet.
YOu can also find a number of shelf stable Indian and a few Thai dishes at many grocers. Target has a pretty good selection.
Cous cous cooks from boiling water. The small immersion water heaters for a cup of coffee or what not are certainly up to the task of boiling enough water for two for cous cous.
I've taken to buying boxes of single serve pouches of mayo, mustard and that sort of thing for trips. Doesn't need refrigeration, right amounts for simple doctoring.
