A tip to save on off-net ATM fees - go buy something at Walmart, and if you pay with your debit card you can get up to $100 cash back with no service charge.
I try to have no less than $100 and no more than $200 cash on me when I travel. I try to keep an assortment of small bills because even if I use my credit/debit card in a restaurant I prefer to leave a cash tip. I usually don't bother using the card for purchases or meals much under 20 bucks.
If you are not a member, join AAA.