Drive from the US to Canada, or the reverse. It is a hell of a drive.
I also drove from St Louis down highway 70 through vale colorado through the mountains north and down into the Salt lake Valley in the early morning then up through the canyons to Cache Valley in Utah. It is a beautiful area. Then on the way back came the northern route over the high plateau of the northwestern United States.
Sure you can fly, but everyone should take some drives to the more out of the way sites like the Black Hills, and old Faithful, and the mountains with all the president's Heads (Rushmore?). It is fun to purposely get off the main highway and travel through national parks and scenic highways. You have to purposely go places like the Corn Palace just to see it.