Hmm. I could probably write a small novel about this but I will try, try, to keep it somewhat short.
Detroit? Don't let the rep scare you. Lots of good places to eat downtown. It has been cleaned up a lot over the last 10 years. On the way up, if you want water, I would recommend going up either US23 north of Standish. It will run along the shoreline on the east side all the way to Mackinac Bridge. US31 will do the same on the west side. Having lived on both sides, I will say the west is better as far as beaches and such but you will easily be adding 2-3 hours going over to that side. There are some nice beaches along the east also but the west gets all the attention. Plenty of lighthouses to stop at on the east too.
As far as the UP, it is a matter of what you want. The Soo Locks are neat to see. Straight up 75 from the bridge. Pretty neat engineering there. Head west from there and hit Whitefish Point. Very cool lighthouse with a great museum there. You can backroad it from there west but it will eat up a lot of time. There is Crisp Point Lighthouse along the shore over there. I have never used GAIA so I do nto know what all it will do. You can find a road that will run into H58. That will take you along Superior shore some and into Grand Marais. Some nice dunes and falls there. Nice area. Hop back on H58 and head west to Munising. This is the Pictured Rocks National Park area. There are also falls by Munising worth seeing. 28 is a nice drive along the shore from there. Several nice spots to stop between there and Marquette. I would say the highlight of Marquette is Presque Isle Park. Gorgeous! You can even jump off the Blackrocks if you are feeling like taking a dip. You can either head over to Big Bay or take the 410 west out of Marquette. Various routes can be made across that area. It is pretty desolate. A nice spot to camp is Mouth Of The Huron. right on the shore. From there you will go over to L'Anse. A that point, you will ahve to decide between heading west or heading up the Kewenaw Peninsula. That is an excellent trip if you have time. Maybe even a night out at High Rock. That has gotten quite popular thanks to several overland videos. If you do head up there, stop at Brickside Brewery in Copper Harbor. Very friendly place! Also if you go that far, take 41 up and 26 down. 41 will take you up Brockway Mountain for a beautiful view from high up. 26 runs along the shoreline for a different but great view. The Jam Pot has good stuff up there too. Maybe hit the Bill Nichols Trail when you go back down south from Houghton/Hancock. It isn't anything rough or difficult but it will take you over 3 old railroad trestles. If you want to go to The Porcupine Mountains, west from there. If you go there, you will have to head back east a bit to 84 and head south for a quicker way. There is a road that cuts across the bottom of the Porkies. You will eat a lot of time up on those roads. There are several waterfalls up near the shoreline. Some at the west end of the Porkies and some further west ear the MI/WI border. If you want o make time, from the Porkies, just head back east to 84 south to US2 . Off to Bayfield from there. We stayed on Madeline Island for a couple nights in 2018. The town on the island is pretty hippie/yuppie/artsiy. We drove around the island a bunch too.
Although it would probably take a couple days, I would recommend a drive over and up The Northshore of Minnesota. That is some beautiful country up there but that could easily add a few more days.
Hope this overlaod helps.
BTW, my brother-in-law lives in Roanoke, VA. We visit him every couple of years. We went last October. He took us up Bald Mountain on one of the trails. He was in his Gladiator and we were in my 4Runner. That was a blast! I can't wait to hit another next time down there.
