Sounds like a great trip.
Check on the Canada Border Services website for information for visitors.
In all of Canada you must also carry proof of having valid public liability insurance in effect with you in your motor vehicle. Canada Border Services at ports of entry are not concerned with this - law enforcement will ask for it under certain circumstances such as an accident or traffic violation. Operating a vehicle without liability insurance is a serious offence.
Businesses may or may not accept US currency, and if they do they may not offer fair exchange rates.
If you spend a lot of money while travelling you will want to shop around for the best exchange rates. We exchange some money at large banks for the best rate when we are planning a visit to the USA.
Have a safe trip
