It sounds like there are a lot of teachers out there that use Realidades and are looking for ways to incorporate TPRS and CI into it, beyond what the TPRS supplement suggests. I typed up this document for one such teacher, and I am sharing it here for anyone else who finds themselves in the same situation. This document is now located in The Comprehensible Classroom’s Subscriber Library
Find the document in the Administrative Items Folder » Textbook Alignment Subfolder
The most important thing to remember is that you don’t need a fancy story or a clever activity to bring Comprehensible Input into an existing unit. CI is the most natural way to use language, because all you have to do is lead a conversation with your students that involves the words or grammatical structures that you are trying to teach. Get lots of repetitions, and your students will acquire the language!!