I'm not a truck driver, but when I travel, whether by car of plane I face a similar problem - taking food that will supply me both nutrition and calories because I can't always rely on finding it along the way.
There are several starchy vegetables that are easy to cook ahead and carry with you. Potatoes, both sweet and regular can be cooked ahead and eaten cold. My favorite was corn -microwave in the husk to cook, stick them in a bag to carry then peel and eat when hungry (I'm allergic to corn so I no longer can eat it
). I find that I can eat and enjoy both potatoes and corn on their own with nothing added. If you have a microwave in your truck, or access to one at a truck stop you could cook them fresh. Potatoes store at room temperature and ideal for this. Corn can be stored at room temp too but deteriorates over time so I would plan to cook and eat it early in the day.
Rice and quinoa are sold in precooked bowls ready to microwave, here's an example
https://www.amazon.com/Steamed-Brown-Or ... B000FIXT2I They are shelf stable so you could store them in the truck for weeks and have as a back up. Serve with left over veggies from dinner the night before.
I wouldn't eat that much beans - too much protein as Dr. McDougall explains. But 1 can of beans every few days could add variety to your meals and are great additions to a basic salad.
If you have a minifridge in your truck you have options of bringing food from home.