What to see in Northern United States?

My girlfriend and I will be driving from the East Coast of Canada to British Columbia. The fastest way to get there is to travel through the Northern United States, an area neither of us are familiar with. According to Google Maps we will be passing through the New England States, Pennsylvania, Ohio, Indiana, Illinois, Wisconsin, Minnesota, North Dakota, Montana, and Washington. We were planning on stopping in or around the major cities but would love some recommendations of places to visit, things to see, or cheaper, more accessible accommodations (in comparison to the larger cities).What to see in Northern United States?
I will hit on a few places in Pennsylvania. If you are a chocolate fanatic, make sure you find your way through Hershey, "The Sweetest Place on Earth." Heading east, you will pass through Amish country. There are a number of things to do there, many of which you can find online. I would definitely find my way to Philadelphia to visit the places where the United States truly began. Independence Hall, Carpenters Hall, and the Betsy Ross House are but a small sampling of things to see there. (Make sure you get a cheesesteak while you are there, and if you happen to drive through Pittsburgh, stop for a Primanti Brothers sandwich.)What to see in Northern United States?
Acadia NP, Maine

Salem MA

Boston MA

Newport RI

New York City

Baseball Hall of Fame, Copoerstown, NY

Niagara Falls, NY

Rock and Roll Hall of Fame, Cleveland

Chicago, IL

Mall of America, MN

Voyageurs NP, MN

Badlands NP, SD

Glacier NP. MT

Seattle, Wa

Olympic NP, WA

Mount Saint Helens WA

Mount Rainier NP, Washington

San Juan Islands, WA