Snacks that travel!

I would say pretty much any fruit should be good to go. They are like nature's candy/snacks and some even have their own wrappers. ;P

Of course theres veggies like carrots, cucumbers, tomatoes, hard boiled eggs, beef jerky, protein bars, chips, crackers, etc.

For actual food there's sandwiches, wraps (again insert meats/veggies/etc.), and much much more. I highly suggest you check out the Bento thread as almost all bentos are meant to be eaten at room temp.

http://community.myfitnesspal.com/en/discussion/10043413/using-bento-boxes-for-lunches/p1

Kind Bars, keep one in my pocketbook and one at work.

Since you have a cooler, one of my husband's favorite lunches is a Kale & Feta salad. We'll make up a large bowl and it keeps pretty well for 3-4 days in the fridge depending on how fresh the kale was to start.

Finely dice a shallot (1/2 a small red onion works too), add the juice of a large lemon, a little salt, and a lot of black pepper. Whisk in about 1/3 cup olive oil. Remove the stems from a bunch of kale, then either chop the leaves into bite sized pieces or you could stack the leaves, roll up cigar style, and thinly slice if you want to be "fancy". Toss with the dressing until coated (taste a leaf or two and adjust lemon juice, olive oil, s&p to taste but don't add a lot of salt just yet (we like lemon so we usually end up tossing in more lemon juice at this point depending on how juicy the lemon was)). Gently toss in about 1/2 cup of crumbled feta cheese. Transfer a main-dish serving size to a portable container and add your protein choice before eating. Our favorite protein choices are the single serve tuna and salmon pouches, leftover grilled shrimp, or diced chicken.

I just reread your post and noticed the part about dairy. Can you tolerate cheeses made from sheep or goat milk? I've used crumbled goat cheese in the above salad too.

Overnight oats! They can be made with plain oatmeal, nut milk, fruit, and whatever you want, pop them in the fridge the night before and then keep them cool until you're ready to eat! Super filling.