For Canada crossing the big 5 are guns (very limited and by permit only), alcohol (limited), firewood (not allowed), cash ($10,000 limit per person) and criminal/DUI record (you won't be allowed to cross). Passports or equivalent are required. Regulations on what is allowed each way are constantly changing so remove your hat and directly answer the questions, don't chit chat or volunteer information. Questions that don't seem necessary may be used to determine if you are being truthful. We've had a couple of refer checks but never a full rig search. US wanted our tomatoes and green onions one year. Restricted fruit/tomatoes with the small labels indicating US or Canada may be allowed. Unopened store wrapped meats are more likely to be OK than opened packages.
We take a little US cash and charge everything on Visa. Our Capital One has a fair exchange rate with no foreign transaction fee. Amex has a foreign transaction fee of 2-3%. Canadian fuel is more expensive so fill before the border and after you return.
Have a great trip.
