My son Seamsealer and I are going ultra-light this month to Quetico.  We went nuts and bought (get this):  powdered peanut butter, powdered cream, powdered milk, powdered shortening, powdered eggs, and of course powdered milk.  I have finally found a powdered milk that tastes great by the way - it is a Nestle product called NIDO.  You can get all this stuff on line - many times under the survival goods guys.  I have been satisfied.  Of course you can't beat farm fresh :-)