Michigan UP is just gorgeous, which is on your way if you're going to Sault Ste Marie. The entire coast line of each side is phenomenal with lots of places you can land your feet in the sand and photograph the grandure of the big lakes in its best form. You have to stop in Paradise, Michigan, and have a catch of the day whitefish sandwich at Brown Fisheries Fish House. It's amazing.
The trek out to Crisp Point Lighthouse is worth it if you have the time and a car that can handle dirt roads that can be a bit rough. The area is gorgeous. Tahquamenon Falls are quite interesting too, with a nice watering hole at the top falls and nice hiking and views of the river and surrounding area.
One of my favorite places I've ever been.

The Minnesota Lake Superior North Shore is breathtaking as well, but probably farther out of your way.

Congratulations on your retirement! Sounds like a fun adventure. If you stop by Minneapolis on the way over, give me a shout. Suzanne Revy has so many good things to say about you that I'd love to meet you in person.