I agree with Canuck54. U.S. cash so the merchants don't have credit card fees. If you can, buy your drinks & food at Perch to support these people who are trying very hard to make your experience there as good as it can be.
Parking at Bobby marina should not be a problem. But yes go when at least one cruise ship is in. Lots of people to approach you if there aren't ships in.
I'm pretty sure those stores are open in grand case at the south end.
You will be glad you went.
If you are flying westjet I'd like to know if planes are full from Canada.
Cheers!