I know Ontario is fairly flat so bear in mind that you are in the mountains. Heading eastbound you are going UP hill mostly with a few downhill portions but just use your trans lower gears and engine to keep a safe speed. No need to ride your brakes... just don't ride your brakes. I tow my 37 ft. TT through there at times with no issues. Waynesville and Maggie Valley is beautiful too.
Whatever you do don't get any idea to go over the mountain through Newfound Gap in the National park. Get to your destination and then go see it in the truck if you want to. That road (441) is not meant for towing so don't even think you can get away with it.