Okie or Ozark American, which ever you prefer, LOL. Medicare has written rules on Canada. Basically, as I understand it, you pay the cost up front, then it gets complicated. If you are just in Canada on vacation, then no reimbursement, if you are on a straight line of travel from where you enter Canada to Alaska, then you may be reimbursed at the normal Medicare rate for the approved services you received.
So travel insurance can be a safety net, if a person thinks the cost is worth it to them. I don't buy travel insurance as I have supplemental insurance as part of my Alaska retirement and it should cover me, even though Medicare doesn't. I have only used Canadian health care once at the Mall in Edmonton. A contact dermatitis problem, from poison ivy I had contacted at our ranch in southern Oklahoma. They had no idea how to charge me so they finally asked how much a doctor's office visit would cost in Alaska. I told the doctor and he told me to write them a check for that amount. I did and a few months later my check cleared my bank.
A lot of verbiage to say that Medicare probably won't cover you in Canada, but they might. Reading the regs or talking to a Medicare rep before going would be best for anyone of Medicare age going to Canada.