We have started traveling through sections of Canada to avoid US toll roads. Cheaper to buy fuel in Canada than pay the tolls. Plus we enjoy traveling in Canada. We purchase fuel at truckstops and have never had any problem with credit cards. We try to make our experience beneficial to both us and our Canadian hosts. Win Win.
No negative experiences crossing the border either way. Have been searched once. We try not to have any items that are restricted. Some crossings are more pleasant than others but no problems. We found that Sunday evenings are not the best time to cross. Prefer early morning on weekdays.
Have a pleasant trip.