We often fish for long periods of time on our boat. For lunch we enjoy sandwiches and lunch meat.
But occasionally I will bake breaded shrimp or Tyson Honey Chicken Tenders and take them along with a small container of cocktail sauce or ketchup. I keep them in the cooler, of course. You could do the same in your truck. Even cold, flat bread pizzas would be nice. Pimento cheese spread is also good. And slices of chesse and lunch meat with some cucumber or other veggies is also tasty.
Leftover chicken is also a favorite.
I will watch this post for some additional ideas!
Enjoy!