Fiction-Reality Interfaces

I have recently referred to two World Science Fiction Conventions attended by Poul Anderson: one real (I attended it); the other fictional (I read about it). However, the fictional Con was held in a divergent timeline so maybe it is real? Fascinating fiction-reality interfaces have been perfected by various fantasy writers. (Our reality is a dream within Neil Gaiman's The Sandman which is a fiction within our reality which means that our reality is within itself.)

Living within a single universe, we imagine and even postulate other universes and can then turn this situation on its head, i.e., characters in a fictional multiverse might encounter our universe among all the others ("An Earth where not even one person has gained superpowers? Seems unlikely!").

Two short stories by Poul Anderson are set in an inter-universal inn and the first person narrator of these stories seems to come from a world like ours. Is it safe to identify this narrator with the author - as we identify Dante the poet with Dante the day-tripper to the hereafter? Commenting on the two Old Phoenix stories from the memory of having read them, I would say that the narrator could be the author although, if I were to reread the stories closely, I might find some reason why not? But, for the time being, I am content to remember rather than to reread.