The few time I've driven across the border, the Canadian guards seemed nicer, smiled a bit more. Current stories are that the Canadians are somewaht more covid exclusionary than driving back into the US. He may be, but if someone isn't the registered owner of a vehicle, that might slow things down.

I wouldn't wave it around, but folks settled out of town just might perceive it as normal, rather than outsider, to see a shotgun mixed in the gear of a wilderness visitor. I'd bet the kid will see used gun racks at gas stops and such. Given the scenario, he might feel a good bit more at ease picking up something sooner rather than waiting for later.