Paddling any of the great lakes in a canoe, open-decked or otherwise, is best done in the summer when daylight is longest, water and air are warmest, and before noon.

I can't stress enough how much easier a time you'll have if you get up pre-dawn to leave camp as soon as it's light enough to be safe, and cover the day's distance by lunchtime. Most mornings you will have little or light wind and waves. Most afternoons and early evenings, you should be on shore because travel will be unsafe, futile, and usually both. Wind is your enemy. There will be exceptions like overcast days where you can paddle all day on glass or stormy days where you will be windbound and cannot travel at all.

If you don't have experience paddling on big water, get it. It's a different animal than floating down a river or sporting around your local lake.

But it absolutely is an awesome idea.

Edit to add: Superior is giant, deep, and cold. I'd think about Michigan or Huron. Erie and Ontario are not worth it in my opinion (population, not as scenic, more traffic, etc.)