Recently used a 14 gallon rubbermaid tote inside a #4 cruiser pack and it was a good fit. It held food for 4 people for 7 days. When I realized how heavy 14 gallons of food was I was happy to be using a well made durable pack. Also there is room to slide a few items along the sides of the rubbermaid but inside the pack (fire grill, fry pan etc.)
Squirrels were a problem whenever the pack was on the ground but did not bother it when it was hung.