All of us like Tuna Mac Salad, served with green salad or fruit. Also, I usually bring along a panini maker and a few deli meats/cheeses. We usually have tacos one night, for which I cook the meat and chop the toppings before we hit the road.
Tuna Mac Salad
You'll need shell pasta, stuffed green olives, 8 oz canned tuna, mayonnaise.
Cook 1 and 1/2 cups small shell pasta, drain and chill. For dressing mix 2/3 cup mayonnaise (NOT salad dressing), and a scant 2 Tbsp juice from the jar of olives. To the pasta add: dressing, 1/4 cup chopped green olives, drained tuna and black pepper to taste.