Ken,
The ship must be de-registered in Canada, which means it’s dropped from Canadian aircraft rolls and its C bumper is removed. Best way to do this is what the FAA calls an “Airworthiness for Export” license. Armed with this, you request US registration including US “N” number. The feds will in due time, license the ship and issue Airworthiness certificate. Get separate bill of sale for trailer. No export fee at this time, but there’s no telling what Mr. Chaos might dream up next!
Enjoy the ride, may take several months,
JJ