Make friends with someone who lives at a catered on-campus college, and bludge off them! That's what some of my friends do.
Generally colleges have hot food served, and then self-serve salad bars that are easy for a non-ressie friend to pinch some of, if they're there with someone.
Failing that, move into a college.
Ummm dried fruit and nuts is great. But I guess more of a snack. You can get those tuna things with biscuits, they're pretty good. Or some soup that takes nice cold. Or soup in a thermos? If you need to buy sometimes, what about things like kebabs or hamburgers? Fatty meat, but salad too, and they're fresh and taste good and keep you full. Sandwiches that aren't soggy are good too.