This widget could not be displayed.
Gallon jugs of water are very lumpy and it would be difficult to distribute the weight, not to mention uncomfortable. And 5 of them is quite a large volume.
Pea gravel is really the way to go; the stones are smooth and small, and not very abrasive. I'll have them in their own bags, so they shouldn't come in contact with the pack material. I'll also be able to use some of the smaller pockets if necessary by wrapping them in trash bags.