Bacteria grows between 40 and 140 degrees so as long as it is outside of those zones you should be okay.You can cook the food and keep in warm in a pot over the fire. As long as the food is fully cooked the keep warm temperature for food is surprisingly low. As long as it is held at the proper temperature it should be able to sit warm for a day or so before you'll have any problems.
Many of the companies you buy the #10 cans from give you an idea of how long an opened can is good for, but many of them are good for a year or more after opening. The main thing is to keep them dry.With just the wife and I eating, how can I save the balance of a #10 can of food open for one meal?