thanks for the answers. Reentering US is not an issue as I have B1/B2. My question specifically was if I will be allowed to enter Canada with COPR and Indian passport from USA with rented vehicle as I can enter the USA with my B1/B2 visa from India.What visa status are you in? why do you refer on B1 when you are already on non-B1 status. You should be able to reenter US on the same visa status using automatic visa revalidation for which you dont need to have valid visa. And certainly your B visa is not substitute for your current visa status.
Yes you can travel via land on rental car/truck with your copr and passport to enter Canada when PR card is not available. Driver license is not travel document.