When we came through Yellowstone in 2011 we realized that the main East/West route through the park is US 20. The very same highway that continues on to Boston Commons. We stayed with it except for Illinois until it crossed I 390 12 miles south of our home in Rochester NY. It could be boring if you don't stop to enjoy the small museums and towns along the way in Nebraska. Iowa was more boring although we did find a Frank Lloyd Wright House just off the highway to stop and tour. Indiana, Ohio, NY and Mass are all chock full of interesting sites. You can read about our adventure on
xctraveler.blogspot.com and go to the archive for August 2011