Regardless of where you are, in america you’re never far from a walmart or a gas station.
People overthink nutrition.
A gallon of milk a day is really enough, though optionally just add whatever food alongside.
Anyone can down a half gallon at a time. Therefore you can get that gallon at once or in halves. Anywhere.
So stopping at a gas station twice a day, or buying a gallon before stopping for the night to drink that night and the next morning is a way to have relatively inexpensive on the go nutrition.
That’s all the nutrition you need.
Five bucks tops for the milk, a couple bucks optionally in supplementary food.
Logistically a cinch.