Assuming the OP was serious with the questions, DEF is available at just about all auto parts stores and at auto dealers parts counters. Do like I do (even in the USA), carry a spare container, it will take you a thousand miles or so until you find a convenient place to replenish.
As to diesel fuel, fill up where the truckers fill, you will get fresh diesel. I did get a tankful of winter grade diesel in Happy Valley/Goose Bay Labrador in July a number of years ago, got symptoms like hard starting and vapour lock. I eventually killed the starter due to excessive cranking.
