I'm hesitant to post this, because I have no idea how to find, or even if academic sources exist for something like this. If pressed, I would point to Civil War memoirs, such as Billings' appropriately named Hardtack & Coffee. Basically, if you don't mind having grounds settle to the bottom of your coffee, you can make it with a pot or a "boiler" or even a tin cup. It's not much more complicated than boiling water and adding coffee. During the Civil War, coffee was mostly issued to the soldiers pre-ground, often with sugar already added to it. I would assume (always a dangerous thing) that cowboys ground their coffee before going out on the range.