Welcome, Basilio and Wendy - and best wishes on your count down to retirement.
I see you are in a spot of "Gods" country (Deep River) We are about 40 minutes south of Algonquin Park.
Peter and I did some White Water Rafting many years ago on the Ottawa River
...and lived to tell about it
We have imported 3 vintage Airstreams. Streamer 23 links will tell you all you need to know. Be prepared and have your documents ready. The only real hiccup with the process is that you can not plate the trailer and must run with documents from the Customs import office. Putting an illegal plate on can get you into some serious trouble if you are stopped for whatever reason. NO plate is better.
Importing newer models has to go through the Vehicle Import Program that is a little more complicated but still fairly routine. And the plate issue disappears as you are issued a sticker that goes in the window of your trailer until you are issued a plate from the MTO.
Good luck with your search for the perfect Airstream.
Please feel free to PM us if you have any specific questions we might be able to help you with.