We had a smaller 1981 Winnebago (Dodge) - it was a solid, dependable coach and if we had not been looking for something bigger would probably still have it. You clearly will know the mechanical things to look for, and can read the DOT code for the tires (I guess Canada has a system for that
), but the real question you are asking is about Winnebago (not Ford or Dodge). So, you get to the other things to consider - first being how are you going to use it? Weekends? Long trips? Then imagine how you would stow your needs.
See if it has the manuals that should have come with it from the factory, ask to see maintenance records. Check the amount of storage space inside and out. Check the appliances, make sure they work (the smell of ammonia from the refrig, means you will immediately need to replace that, for instance.) Does it have a generator? Does it work? How many hours are on it?
Over all, I would not be worried about Winnebago quality, only how well it has been maintained.
JoAnn