I've done bits and pieces of it in the Southwest, but most of my experience has been with the parts remaining between Chicago and St Louis. Here are a few pictures of those parts...
It starts in downtown Chicago, in the shadow of the Sears Tower.
In Illinois, it now mostly serves as an access road for I-55. You can see the interstate off to the left in this southbound photo. I suppose it isn't very exciting once you get past the roadside attractions, and the general thrill of its historical significance... and that does wear off a little.
Here is an example of one of the famous roadside "attractions." This is south of Waggoner, IL. It's called the Our Lady of the Highways shrine.