The night before, combine coffee and 1 qt. cool water in a Nalgene bottle and shake to combine. Set aside in a critter-free spot overnight, such as a bear canister.
In the morning, strain coffee through a nut milk bag into a 2-qt. saucepan. Heat to simmering, stirring, then divide among four mugs. Heat milk in pan, stirring, then froth with a milk frother. Pour over coffee.
*Find reusable fine-mesh nylon nut milk bags such as SoSoft Brands at natural-foods stores and amazon.com, and milk frothers at kitchen stores. Peak powdered whole milk is rich enough for coffee ($17/900g; amazon.com).