If you are going to be within "civilized" areas throughout the day and camping at night, this can be as easy or as complicated as you want.
If you carry a hydration pack, fill it to the brim during your last stop of the day. If you can, fill it with ice (ask nicely or offer up $1 to the clerk at the gas station to get the ice from the fountain so you don't have to carry or waste a whole bag).
Plan for anything you buy to be eaten fresh for dinner then store what's left for breakfast. Lunch is typically eaten on the road. You can have cheese, meat, etc. as long as you cook it within a reasonable time since you won't be able to keep it chilled. Tortillas are the perfect camping bread.
Bring seasonings & spices with you in small baggies so you don't have to buy more than you want to have to haul home after the trip is over. I also bring a small travel shampoo bottle with olive oil and some folded-up foil pieces from home.
Typical dinner: Steak with onions, roasted veggies or a potato, and beans. Pop the lid on the beans and stick them in the fire or into the bbq coals, wrap the tater in foil and do the same. (the white blobs are fry bread - I tried those instead of tortillas and they aren't worth the effort)
Typical breakfast: Cut up what's left of the potato, onion, and steak. Mix with eggs and pile into tortillas. Don't forget some fruit!
The next night was pork chops with squash. We grabbed an artisan bread from the store and it's the large thing in foil off to the side warming up.