At border areas, both Canadian and US money is good... even at restaurants, stores, etc.
I have never had a problem at Rainbow Bridge, either coming or going... wait was reasonable and the border guys
usually aren't nazis (the Peace Bridge on the other hand...

). Never crossed at the Bluewater, so I can't help you there, sorry.
As far a travel through Canada... should be smooth sailing; you won't be anywhere near Toronto highways, that is the only real problem spot. As far as the people, I have never met a un-nice Canadian.
Ride safe
