Do you not have a fee-free debit card? The rate you got from getting the cash in advance in the US is probably far worse than what you'd get from pulling cash out with a Schwab card from an ATM (or even just exchanging USD north of the border).

In any event, as already noted upthread, Canada is very card-centric. Although some places only take Interac, which is the local debit/POS network.

EDIT: How are the leaves in Quebec City? That's one of my favorite places. I love going in the middle of winter, never actually been in the fall.