I thought that headline might grab some of you!
It occurred to me when reading "The Scouring of the Shire" to the kids the other day, that "The Scouring" could be seen as Tolkien's answer to That Hideous Strength. The Lord of the Rings was written after THS. In fact, wasn't there something about Lewis and Tolkien challenging each other to write stories--Lewis's was going to be a space story and Tolkien's a time story? The Space Trilogy vs. LOTR, which is set in the far reaches of the past?
Compare and contrast Frodo (wounded, tempered by his personal failure) to Ransom (wounded, but having been successful on Perelandra). Gandalf (absent because they don't need him any more and his mission is done) to Merlin (who had to be invoked deus ex machina). You could even compare and contrast the Studdocks with Sam and Rosie. Then there is the almost vengeful violence of the end of THS vs. Frodo's admonition to avoid violence if at all possible. No hobbit should be killed even if he really went over to the other side vs. Wither and Frost.