When I grew up in Overland Park KS US 50 was a stones throw away. They changed the route since then, now that part is US 56. So if you want the old route follow US 56 by Kansas City. My closest drive-in theater was called the “New 50”. I think it was because it had been widened to 4 lanes and then designated as part of I-35 through that section.
Every US highway has a wikipedia entry, and state by state articles for many of them.
Have a great trip!