The Wade Library is located in Wheaton College in Illinois. They have over 2000 original letters from C.S. Lewis along with his writing table and, wait for it, THE WARDROBE! I actually made an appointment to tour this private library and got a chance to touch the WARDROBE. Huge fan of his. I credit his book, “Mere Christianity,” with making me a Christian.
Mere Christianity is excellent. Have you read "The Great Divorce" yet? I think it is one of his best if not his best book (close-run thing with "That Hideous Strength". I found out not too long ago that the title of the latter is from a very obscure 16th c. poem by a Scottish author.)