What time of year are you going? You'll probably hit the Grand Tetons before Yellowstone, and leave plenty of time for Yellowstone, but if it is in the next couple of months check and make sure you can get in, Winter is really harsh there. The Buffalo Bill Museum in Cody is really nice, and Devil's Tower is OK.
The Black Hills in South Dakota are pretty nice, especially Custer State Park. If you can hit the Badlands in South Dakota early morning or before sundown, the wildlife is out then and the colors will be much better than during the mid day sun. If you like a good old fashioned cheesy tourist attraction stop at Wall Drug.
Between Indianapolis and Columbus is Dayton, home of the National Museum of the United States Air Force. It is the finest aviation museum in the US, and probably the world. It is large, full of aviation history, photographer friendly, and even free. You can easily spend a day there, tripod required. There are some other things in the area, if you like nature the Yellow Springs area is special. Columbus is not known as a touristy city but it has a lot of different things to photograph, street shooting along High Street in the Short North is interesting, it's an area with a big nightlife, lots of galleries and restaurants and the sidewalks are usually packed. If you go through in the Summer there are a lot of festivals. Southeast of Columbus is the
Hocking Hills, a great place if you are into nature, it might be a little too far off your path, but it's worth the trip. In Pennsylvania, don't miss Gettysburg.