Elwin Ransom
Elwin Ransom may be based on C. S. Lewis' friend J. R. R. Tolkien ("Elwin" means "Elf friend" in Anglo-Saxon), though he seems to have autobiographical elements. In "That Hideous Strength" Ransom, with his royal charisma and matter-of-fact breezy acceptance of the supernatural, appears less like Tolkien than like Charles Williams (or some of the heroes in Williams' books).
Warwick
J. R. R. Tolkien seems to have been very influenced by Warwick (where he was married in the Catholic Church of Saint Mary Immaculate) and by its Mercian connections: Lynn Forest-Hill, in an article in the "Times Literary Supplement" (TLS 8 July 2005 pp 12–13) argues cogently that two important settlements in Tolkien's work were modelled on Warwick — Edoras closely on the early town, and Minas Tirith more remotely on the Norman; and that aspects of the plot of "The Lord of the Rings" are paralleled in the romance known as Guy of Warwick. Christopher Tolkien, in "The Book of Lost Tales", stated that Kortirion, the main city of Tol Eressëa, "would become in after days Warwick."