Pan bread: I put 1 cup flour, 1 tsp yeast in a ziploc bag. Add salt & dried herbs to taste. On the boat, mix flour in a bowl with just enough water to make the dough. Let it rise a couple hours, then form a round loaf to fit a frying pan. Cook with cover until one side is light brown then flip & do the other side.
I don't like the mountain house stuff either, but I will take rice mixes that you can get in the grocery store.
If you have kids, Mac & cheese is always popular. Add a small can of peas to add some veggies.
Soup cups are very handy, come in a lot of variety, and are nice on chilly days.
In addition to tuna, you can get canned or packets of chicken or beef. I keep some on board to add to dishes to change things up.
A small set of spices, some olive oil, some Tabasco, etc... gives you more options for variety.
I also keep some of the packets of ketchup and mayonnaise on board. I don't use them enough to warrant a big jar. I do keep a big jar of mustard because I like it (which does not need to be in the fridge BTW).
Pop-tart or Belvita breakfast bars are a quick breakfast.
I admit I do keep a selection of chips, doritos, etc. I also like meat snacks and cheese snacks.
I have a small fridge that fills up fast with fresh milk, fresh fruit & veggies, salad mix, fresh meat & cheese.