This is a tough and broad question. You can keep things really simple: cereal (or granola and yogurt) for breakfast, sandwiches for lunch and dinner and snacks to fill you over the course of the day – no stove needed. Or, you can go hog wild: omelets (or eggs Benedict) for breakfast, deli sandwiches with all the fixin’s for lunch and steak and lobster with local sweet corn for dinner.
It all comes down to what gear you have and your desired efforts.
PRO TIP: Cook as much of your meal at home and simply warm it up on the river. Sloppy Joes, fajitas and pasta sauce are all great examples of “easy warmups” on the river.