We'll be driving from NC to our family cabin in Northern Wis in a couple weeks and planning to go up through Michigan. We have a little more time this trip, so looking at alternatives to I-75 the whole way up. Not looking for things to do, per se, just a more scenic and relaxing drive--photo ops along the way being a bonus.
I did the Lake Michigan coast up to Sleeping Bear last fall, so the obvious choice is US-23 along Lake Huron. I did part of that a few decades ago and remember it being nice, but slower than I expected. Are there any nice interior options, like M-33, or M-65? It'll probably still be a 500 mile day, so we don't want to be going TOO slow the whole way

Thanks for any local knowledge or experience!