First suggestion is to get your dog his/her own pack and make them carry their own food, if your dog is large enough to do so. Our 80# dog carried enough food for both of our dogs in this
Palisades Pack This website has dehydrated dog food, but it's expensive if you have a large dog. You can order 5 free samples (do have to pay shipping), our dogs loved it. Just make sure you slowly introduce the new food prior to your trip to avoid an upset tummy.
Dehydrated dog chow