Add
Metric conversion chart to your "favorites" list. Miles/Kilometers is on the speedometer, but height clearances aren't. Also hit an American Express office or your own bank for some $CN. Amex offices usually have foreign currencies on hand, but your local bank may not, so don't wait until the last minute. Once you're away from the border, businesses won't know the exchange rate and may not even accept U.S. Money.
Gas and Diesel is another story. 1 U.S. Gallon = 3.8 Liters. Best bet is to fill it up. They pump the gas and that's not an option. And pay by credit card. Just like here, prices vary, sometimes on a daily basis. Don't try to figure it out. You'll sprain your brain.
Coffee in Canada is sold by Tim Horton's stores. They're everywhere like Starbucks here.