I rode Jefferson Lines from Grand Forks to Winnipeg in 2003. The service had been around a few years, may have been a Thruway bus contractor with another bus company prior to then, and connected with the Empire Builder. The name "Triangle" comes to mind. JL ran it twice a day. I had gotten off the Empre Builder at West Grand Forks at 5am and took a taxi into town, ate breakfast at a tacky Harvey's adjacent to a tacky bus depot.
It was a July 1, Canada Day. There were just two of us on the bus and one automobile at the border. Canadian Customs was polite but wanted to me to get my luggage off the bus, search it, see my VIA Rail ticket to Sudbury, though I told him I was to get it at Winnipeg staion, but showed him my itinerary, which had me leaving Canada on the Maple Leaf a week hence. What he really wanted to know is when an American is getting out of the country. He also stamped my passport and wrote July 8 on it. No Canadian official had stamped my passport, ever or since. He basically had nothing to do but focus on me.
Several years hence, Jefferson Lines ran the business down, first cutting one frequency, then diverting the other from the Winnipeg downtown bus terminal to the airport, then killed it, disliking having to put up with Customs.
Winnipeg is a major Canadian city, but with VIA Rail being what it is, some small replacement bus companies, and Greyhound's demise, there is not much public transportation to network with, for a bus or a train.
Great Falls - Shelby Amtrak (who wrote bus tickets) - Sweetgrass - Coutts, direct connection to Greyhound Canada at the border to Calgary - that was different matter, averaged 21 passengers per trip, but Rimrock Trailways was financially failing, flunking US-DOT inspections, and killed it because they said their break even point was 25 (then run a smaller bus). Very hard to bring back now even though there was a proven market, though there is county bus service between Shelby and Sweetgrass, but nothing on the Alberta side.