If it's a roundtrip, you might consider going through Canada one way. My late wife and I spent our last vacation doing just that. We visited my brother in Minneapolis, then headed through Duluth and up Lake Superior's North Shore. I've been all over the Rockies, Alaska and Pacific Coast, and that North Shore drive rates right up there with the best of 'em -- actually reminded me a lot of Alaska. It was a very pleasant camping trip, but it's been 20 years and I can't remember the exact route we took. We crossed back into the U.S. in NW Vermont, then headed to the Maine coast, and from there followed I-95 to NYC.
We came back west on I-80 all the way, as we had a wedding to attend in Iowa and I wanted to drive through Nebraska for a change. We definitely took the long way, coming and going.
I-80/I-90 would be the shortest. You might ask specifically about the road surface condition of I-90 through Minnesota. The last time I was on it, it was pretty rough, but that's been a couple years now.