If you have to make a lot of sandwiches, try the assembly line method: Lay out slices of bread, spread each slice with butter, mustard, mayo or any other spread you are using. Go down the line and add toppings, finish with top slice of bread, then wrap.
For easier spreading, freeze breads first, then make your sandwiches. This can also help keep foods chilled and it will be thawed in time for lunch. " Use frozen ice packs to help keep cold foods cold.
Freezing drinks like juices and iced teas can also help keep foods cold, and who doesn't prefer a cold drink (keep in mind that the containers are likely to sweat while thawing, so wrap you food well so it doesn't get soggy).
For a nutritious and low calorie lunch, pack some raw, or lightly steamed (then chilled) vegetables such as broccoli, cauliflower or carrots. Add a small container of dip (or individual package of salad dressing) and you've got a great snack or lunch addition.
Here are a couple of fun sites on finding food while traveling: