Trip permits can be confusing. Different sites say different things. Glad that I bought my car from a dealership with temp tag/registation and don't need to buy trip permits.
http://www.importcartocanada.info/category/faq/
What kind of Documents and Paperwork are needed to Import a Car into Canada?
"Registration - If you are buying from a dealer, they will provide you with temporary permits, if not, you will need to go purchase one from the local Motor vehicles office. If you are driving through more than 1 state on the way back to Canada and did not purchase from a dealer, this will be tricky because you will need a temporary permit for each state that you drive through. Once you reach Canada, your American temporary permits are sufficient enough to drive home with, as long as you have the Completed Form 1 (see below) with you. "
http://ucanimport.blogspot.com/2009/...temporary.html
"With a trip permit purchased in one state, you may operate the vehicle through all states that fall between your origin and your destination. For example, if you purchase a trip permit in Texas, you can use that permit to operate your vehicle through all the states up to the Canadian border and to your residence. You are not required to purchase a trip permit for each state."
http://www.auto-broker-magic.com/Canada_Import.html
"3. After purchasing your car at a U.S. Dealer, they will issue you a one-month temporary license plate. You can drive in the U.S. and Canada (while you are completing the import process) with the temporary license during this period."