Logistics
Have a third driver that only does the crossing part. Say, start the first dropped off truck Canada to Us, cross border, dropping truck getting second to go North TO Canada,, dropoff Canada side, next truck south to US , cross, drop off. Could be ten miles in either side. But the key is logistics of having a Crossings Only driver. He can show up at first spot in his pickup truck, work eight to ten hours, end up at start, and drive home. Only crossing border all day.
Good idea about the third driver. Although I know of some folks that won’t be in the same room with an unvaxxed person, much less get into a vehicle just occupied by one.