I know its stating the obvious, you all MUST have passports to enter back in the U.S. I use my credit cards for most all purchases and Canadian currency for small stuff. If for some reason you must use U.S. currency, many will not take it and those who do will give you back 1/1 exchange rates, not so bad now but back in the 80's when it was 40/1, it hurt. Most say its not needed but it would be a good idea to get an Inter Provincial Proof of Insurance card from your U.S. insurance agent, like many things, you don't really need it until you REALLY need it, ask your agent, they'll know, it takes a few minutes to do. Sorry, kind of off the point but a lot of folks don't know this stuff until its too late. Good luck, its a beautiful area.