So I tracked down this further information, which isn't much, on a website with the map images:
In 1973, California State University geography professor George Etzel Pearcy suggested that the U.S. redraw its antiquated state boundaries and narrow the overall number of states to 38.
Pearcy's proposed state lines were drawn in less-populated areas, isolating large cities and reducing their number within each state. He argued that if there were fewer cities vying for a state's tax dollars, more money would be available for projects that would benefit all citizens.
Because the current states were being chopped up beyond recognition, part of his plan included renaming the new states by referencing natural geologic features or the region's cultural history.
While he did have a rather staunch support network—economists, geographers, and even a few politicians argued that Pearcy's plan might be crazy enough to work—the proposal lost steam in Washington. Imagine all the work that would have to be done to enact Pearcy's plan: re-surveying the land, setting up new voter districts, new taxation infrastructure—basically starting the whole country over. It's easy to see why the government balked (though that doesn't mean it was a bad idea).
That encouraged me to find out more about G.E. Pearcy. He's not on Wikipedia but does seem to have been a major geographer in his time. He had two posthumous books in 1986. WorldCat provided me with his book, "A Thirty Eight State U.S.A."
Well, at that point, of course I had to find the book! I borrowed it through interlibrary loan. It has the maps you see above (though in my book they're b/w) and yes, it does indeed go into detail why he districted the way he did, and why he renamed each state the way he did. It's a bit dry at times (it is by a geography wonk) but I feel like this could be a reference work for an AU. It's just a simple background piece - something the characters never think about, like we don't think about why our US states are the way they are in everyday life - but it would easily show that this world isn't the same as ours, without it being too out there, if your AU just needs to be a little different.
He also admits he doesn't go into the entirely separate problem of state capitals, and there are indices and tables in the back.