When you say Google, I presume you mean Map Quest right?
I did it both ways from St. Ignace to Duluth, shortest time/shortest mileage.

Not much difference, they both take you up to 28 from St. Ignace, then West on 28 to Wisconsin and up.

I think there's better route that avoids going thru the major cities along Superior and would be my choice.
IF you can get a physical road map of the UP, I think my alternative has some merit.
Might be a few miles farther, but you save the time not going thru the cities.

From St. Ignace, I'd take 2 WEST, to Rapid River, jog south on 2 and pick up 35N in Gladstone.
That takes you up to 28, west of Marquette.

I think you can probably average 60-65 on 2, the same on 35N and on 28, I'd just go with the flow, not the fastest/slowest.
Check it out and see what you think?

hey,paddle guy, Did the Badger (Ludington to Manitowoc)survive to run this year? I love that thing. I'ts like a cruze.

Badger is still alive and kicking, but the environmentalists are doing their best to shut her down.  Apparently, burning coal is a bit offensive to some.  There has been talk about retrofitting her with new engines, but with competition and increased fuel costs, it will be a rough sell. 

Could be the end of an Era.  Personally, I'd hate to see that old boat go. 

Regarding average speed across the UP...I guess I've never really timed it. Based on the length I travel, I know that I will be staying at in Superior or Duluth on the first night.  I don't really care if I get there at 6pm or 8pm or 10pm for that matter.  I'd rather have a relaxed trip and avoid congestion.  After all, that is one of my main purposes in taking a vacation, to get away from crowds and congestion.  I would just as soon start my vacation the day I leave home, not the day I get to the BW.  The road is mostly two lane highway with passing lanes.  Posted speed is 55mph, but it is wide open highway and if you actually drive that slow, you will not make any friends. 

Perhaps, the average speed is a result of the frequent stops to "smell the roses," and skip stones in Lake Michigan and Superior on the same day and/or breath in the moist air while standing underneath a waterfall. 

Have agreat trip!

I hate driving through Chicago more than is rational or healthy. When I do it I just bite the bullet and use the toll road of 294. It is by far the fastest way through and it is worth the insane tolls that they charge now (even taking into consideration how much I retch at paying tolls to IL).

The route over the Mackinaw and through da U-P is a very scenic drive, but VERY slow. Hwy 2 will take you right across to Superior/Duluth but is very winding and slow with a lot of small towns. Very enjoyable for a drive, but slow. Did I mention it's slow?

If you do take I90 to I94, I'd suggest taking Hwy 53 North @ Eau Claire instead of over to MN and up I35. It's basically an interstate @65 MPH but more direct and more scenic. The first time you come over a hill and see Lake Superior is memorable.

However you get there, may the breezes be gentle on your back.

631, You know the I-Pass tolls are half the manual tolls?? Plus you don't have to slow down to get through them. Once you get one you'll like it IMO.
Think of Chicago as a portage. Slower and a pain, but not really as long as it seems. It's all your state of mind. Sometimes traffic seems to creep forever. But if you stop to eat and relax, it's moving again and you're on your way.
Enjoy your return trip. North shore of the big lake is longer but good. It'll extend your post tripping mood a bit too.