Hi Old One, It's the Newfoundlander again.
When I've gone south, I've found the credit card most reliable. I tend to head for small places, which may not accept a debit card from a Canadian bank.
Get a $100.00 from a Canadian bank before leaving.
U.S. banks hit you with much higher transaction fees. You see, in the U.S. banks are traditionally local, whereas here, they are mostly national, or at least regional.
Bank of Montreal Daily Exchange Rate Page That is the prime exchange rate for changing large amounts of money. It's saying prime rate would cost you $1.1607 Canadian $ yesterday @ noon. You would probably have to pay something like 1.165 with no additional fees at your bank.
Have a good trip.
the not so young one