Depending on the expected weather, this may be a great time to leave the stove behind. You've got enough to think about, in terms of gear while you're out on the trail, so why worry about a stove, fuel amount (too little?/too much?) and the attendant parts needed to make a stove be efficient.
As a general starting place for food, you should be aware of the calories per serving and the weight per serving from the nutrition labels. If you pack foods that are in the 120 - 150 Cal/ounce range, then you are optimizing the amount of calories you carry in the fewest ounces you have to lug around. But, that's more important for when you need to be careful about how much weight is in your pack and the available space in your pack/bear canister (if one is needed). For an overnighter, not so much.
Trader Joe's is a great place to shop for backpacking food. Tortillas make a great base for thick pieces of cheese and salami and maybe a little mustard. Olive oil is very calorie-dense and a little poured into or on anything is nice. Cheese bagels are tasty and potato chips are often high calorie (Pringles are 150 cal/oz, a number that is not so easy to reach!). Trail bars or granola bars are easy b/c it is one serving and usually pretty high calorie. Trail mix is great. Plain nuts, too. Chocolate is calorie-dense, too, so have a serving after dinner (nice with a little nightcap, too).
Finally, repackage your food into ziplocs so it takes up less space. It can be helpful to organize into serving sizes so you know how much you should eat, rather than just eating a whole bag of chips or something.
As you start to backpack more and more, you can always experiment with canister stoves, alcohol stoves and esbit/solid fuel stoves to find the right stove to add to your gear.