redibrek cooks quicker on a camp stove, you can add dried milk powder if you don't have milk
porridge can be ok with no milk at all (made with just water)
think about a cool box etc
in france fresh milk (lait frais) as oppose to UHT isn't as common in smaller shops.
skimmed UHT doesn't taste as weird on cereal/ in tea as full fat UHT for some reason.