I guess the first step is learning to cook well enough that you can enjoy what you're cooking...
Any camp stove along with a Dutch oven, a couple of pots and a frying pan should do, add a spatula, and a pair of tongs. I use dollar store dishpans for sinks, dollar store spray bottles for water delivery, and a simple ice chest for refrigeration. If you want or need an oven there are numerous stove top ovens available too.
One of my favorites if I don't feel like cooking is to basically make myself a sub sandwich, except on a tortilla, roll it up and chow down. The ingredients are up to you. I like tortillas because they're cheap and they last a lot longer than bread. I also like to keep smoked meats around. I can make a tasty meal out of a nice piece of smoked meat, some potato salad, and raw veggies. No cooking required.
I also like to eat out a couple of times a week, but it doesn't need to be expensive. I tend to go to the bar & grill type places. Often they have great food at really cheap prices. Two nights ago I had a 12oz New York Steak with a loaded baked potato, and garlic cheese toast for $6.95. If I go into somewhere new and I don't like their menu or their prices, I just leave and go find someplace I like better. If you're a senior, some places offer senior discounts as well, never hurts to ask. I also usually eat my dinner around lunch time, or during happy hour, the prices are cheaper.
Eating good doesn't have to be a budget breaker. Potatoes and onions are cheap and keep well, and there's almost unlimited ways to make potatoes. I also like to keep those green olives around, stuffed with pimentos. In spite of the warnings, I never refrigerate them, but they've never gone bad on me. Hot or cold, hard boiled eggs can make a nice treat too.
When shopping, if you really look, there's tons of great food you can get that doesn't require refrigeration. Heck, you can even buy pre-cooked bacon now! Canned hams are fully cooked too. Don't forget the deli departments in stores either. Many offer fully cooked food cheap, or you can use their microwaves to heat up something bought elsewhere in the store. I don't have a microwave in my van, and don't want one, but I have never even been questioned using one in any store, even convenience stores, and even if I bring my own food in to use their microwave. I've even taken my own leftovers into stores and reheated them with their microwaves. It's a great resource.
Whenever I hit a new town, I try to find a local meat market. Sometimes they're cheaper than the grocery stores, and the meat is usually a much higher quality. I especially like taking steaks straight from the meat market to my grill or frying pan. Yummmmm....