Howdy!
We've been traveling in the maritines in Canada now going on three weeks. We're in Newfoundland and took a short trip to Labrador. We have had no problems using US currency when we did not have Canadian money on hand. Even the toll booth at in Nova Scotia took US. We us credit cards for most everything but have found places like campgrounds that except cash only. Check with you debit card company. Our debit card is block from being used outside the US. I had to contact them to override it. They stated if I did use the debit card outside the US they would not cover any fraud. We opted to use credit card only. Make sure you have your pin number to your credit card if you want cash. Its not like a debit card you can get extra cash at the checkout. Lesson learned we never use our pin on the credit card, had to contact the credit card company to get it. Problem is that they have to mail the pin number to you. It took awhile to get the number traveling.
"Happy Trails"
Chiefneon