My daughter likes sandwiches like almond butter & honey, cream cheese & jelly sandwiches, egg salad & tomato, chicken salad with nuts & cheese and salami & cheese on pita bread or flat bread.
She likes turkey wraps with cream cheese, spinach leaves & cranberries.
Pasta salad with feta cheese and shredded carrots.
In her thermos I've usually put leftovers from the night before. BBQ chicken cut up & mixed with sweet potato, Pasta (my kids fav is spinach pasta with alfredo & cauliflower), soup, stir fry, casserole...stuff like that.
I don't have any suggestions on how to hide the veggies in her food except to hide it in pasta. My kids like raw veggies with dip. My son likes his carrots steamed and then cooled in the fridge.
I will also pack stuff like fresh fruit in a tupper-ware container, string cheese, Cliff bar, rice cakes, trail mix, apple, yogurt in tupperware with granola, veggie chips or BBQ pita chips.