What I often do is weeks before we leave, I double up on some of our favorite recipes and freeze half for our trip. I am also on the lookout for simple, few ingredient meals that take little time to cook and I collect those recipes. (I find a lot of those on the back of jars or boxes)
I also collect recipes for campfire meals, like cook in foil in the fire meals, cause if we have a fire, I ain't gonna waste it.
We also buy a Costco rotisserie chicken as the price is right and I make three meals from it (only 2 of us). I do the same with a big steak, making more than one meal with it.
I always make a menu for the days we are going to be gone and I never stick to it, but at least it helps to know that I haven't forgotten anything important
I don't try any new recipes on the road, I never cook anything complicated or with lots of different ingredients and we will have breakfast meals for dinner, sandwiches for breakfast and even leftovers for breakfast.
And on our last day out, for breakfast, we have Wat the hell eggs. Anything leftover that looks good goes in the frying pan and gets scrambled with eggs