108 miles, 10000 feet, and a lot of gravel. I think that's like riding 150-180 miles (or more!) on rolling paved roads.
I've stashed gallon jugs of spring water on a route. It's easy to tuck them out of sight off the road. It would be refreshing to have a gallon per person -- fill all the bottles, drink some more, and wash off the road grime with the leftovers. I would worry about a food stash, perhaps critters would get in it.