I imported a truck from the US. I had to file the paperwork 48 hours in advance with the US customs to export the vehicle and meet the other RIV requirements. Most used vehicles are OK to import but you should check first. A Canadian resident can license a vehicle in Arizona with Arizona plates so you can drive it down there and use those plates to get it to the border when you are ready. After exporting on the US side and importing on the Canadian side by paying the RIV fee you would need a permit to get the car home and then it would have to be inspected before you could get a Sask. license. I didn't license mine in the US but got a permit from the DMV and a 7 day travel insurance card from SGI to get me home.
SGI now allows Sask residents to leave a Canadian licensed vehicle in the US all year if it is OK with the juristiction you are living in. Just changed two years ago.
Brian