Mix ground coffee with lukewarm water in a 1:4 ratio and let it sit for 12 to 24 hours. This creates "coffee concentrate". Mix the concentrate 1:4 with water to make your final coffee. (Tweak final ratio to taste: these ratios are set to my personal taste)

Even if you use cheap no-name coffee from grocery stores, the coffee tastes great. Grinding your own beans will result in fresher coffee.

The purpose of "concentrate" is that "concentrate" cold brew is easier to process (less to filter), and easier to store. You can pick up bottled water virtually anywhere in the USA. So carrying around the concentrate is easier.

You can also do cool things with concentrate: like make espresso (add milk instead of water), or "impromptu hot-brew" (boil some water, add the concentrate. Since you have 4:1 hot water to concentrate, your temperature will be 80% of the hot temperature).

With 4:1 final mixing ratio, a quart of concentrate becomes 1.25 gallons of coffee, more than enough for most trips.

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"Ball" mason jars are pretty universal in the USA. I'm pretty sure they're sold everywhere (more common than quality coffee at least, lol). So you shouldn't have any issues getting mason-jar equipment for storing liquids.

Just don't use their leaky white-plastic caps. Use their gray "leak proof" caps or their steel-caps if you actually want a liquid-tight seal.

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Alternatively, drink McDonalds coffee. Its actually not bad. I know plenty of foodies who avoid McDonalds EXCEPT for their coffee.