I made something tonight that would be pretty easy at a campsite (as long as you have a cooler). I crumbled/cooked Bob Evans sausage and added eggs to the same pan (along with the cooked sausage). When the eggs were cooked, I spooned the mixture onto a tortilla and topped with cheese. It may not be the best meal for a hot day, but I'm all for recipes with 4 or less ingredients :-)
If you're feeling fancy, you can add sour cream and/or salsa.