Hawk,  do a search for "fresh food" or "keeping food cold" and you will probably find several threads about keeping food cold.

just in case you don't know, it is not legal to bring those bottles of powerade and Dr Pepper (and the cans? or jars of applesauce?) into BWCA or Quetico.

Quetico rule #1 Can and Bottle Ban - Containers of fuel, insect repellent, medecines, personal toilet articles and other items that are not food or beverage are the only cans and bottles you may bring with you".  


From the Superior Nat'l Forest Website / Wilderness Rules and Regulations;   "CONTAINERS   Cans and glass bottles are not allowed.  Containers of fuel, insect repellent, medecines, personal toilet articles, and other items that are not food or beverage are the only cans and bottles you may bring with you."  


I believe you could pour your Powerade into reusable water bottles and still be ok.  Those individual serving size plastic packets of applesauce and fruit cocktail would also be ok, I think.