As far as routes go, pretty much any interstate in the US will accommodate you and get you from point A to point B with the least number of stops. However, driving interstates is pretty boring too. If you are wanting to see and visit the local culture, then you need to plan routes that are not interstate.
Not knowing how much time you have or what route you are wanting to go, the chances for Boomdocking West of the Mississippi River are pretty good. Everything East of the Mississippi River and the farther East you travel, toward the Atlantic Ocean, Boomdocking becomes less and less available. There just aren't public lands available like West of the Mississippi has.
This may drive the routes you want to take.
Virtually every State in the U.S. has much to offer by way of camping, sites to visit, and things to do. One thing we enjoy doing is searching on the internet for "Weird" stuff, like "Weird Indiana". A search like this will bring up all kinds of oddities, things not on the main tourist routes, and some pretty unexpected places to see, everything from Ghost sightings, to strange architecture design, to paranormal, to historic oddities, science oddities, and even people oddities. For example, Fairmount, Indiana is the home of the 1950's James Dean movie actor legend. He is buried at the cemetery in Fairmount. The movie "Hoosiers", the final basketball game showing the state finals, was actually filmed in Frankfort, Indiana at the Frankfort High School Gymnasium. And don't forget about the "pink elephant" in Fortville on Highway 67.
Basically, when I'm saying is, anywhere you travel can be a fantastic adventure. Don't get hung up on visiting the "big attractions" where you have to stand in line for hours for a 30 second thrill, when there are millions and millions of other items to see and do, which can be more meaningful. The "Weird" or "Strange" internet searches return some pretty interesting stuff.
