Connecting to the text - Discussion, summary, Integration ideas
"Each guide provides age-appropriate discussion questions, and some may also curriculum connections, lists of and lessons about relevant vocabulary, literary devices and grammar points, and more."
The Digital reading bundle that we have at the Elementary schools from Orca is aimed at an Intermediate (Middle School) interest level, but the books are still written mostly at a grade 3-4 level. (Some are even lower)
Take a look at the teacher resources on the Orca main page. The summary for each title gives the actual reading level for each story as well as a rich set of activities to extend the use of each title.