Ditto the small bills for campsites. Ditto the $100 or so for the emergency motel stay in a violent storm and the phone lines are down, no credit card approvals, and they will give you a good discount for cash (no, I'm not making that up). Ditto the debit card to replenish cash--the USPS will give you $100, some large grocery stores, $200. And ditto the credit card bills for itemizing expenses later on. Pretty much ditto everything above.