I didn't realise there were ones after Abroad either until maybe last year, when I read of Mars out of interest. It was workmanlike, but not dissatisfying; a little by-the-numbers, but the setting was handled well. (Ok, I have seldom had reason to complain about settings with Duane).

Hmm re. Runyon. I am...not familiar enough with actual!Runyon to tell, I think I will conclude; the character here is a lovely poignant, unnamed shadow in his own life, speaking only through his notebook and the magic of the cat-wizard communication. He is a primary protagonist, yes, and the cat-vision of his life and loneliness is used to draw him in quite lovingly.