I use the tea bags used for loose tea, just with coffee instead. I get the bags at the local Whole Foods store. I just dunk the bag up and down to extract the coffee. No mess, no fuss and good coffee. Good for short or long trips, a box of 200 filters weighs 4 oz, so you can take enough for any length tour. (I'm assuming that in tour longer than 200 days, you would be able to find more somewhere in the last 100 days : )

Pour boiling / hot water over coffee bag, dunk, discard bag, drink.

For backpacking I make them up ahead of time and just put the sweetener right in with the coffee. Used coffee bag goes on the campfire if it's burning hot enough.