The Sassafras series novels are on a 5th grade reading level, so a middle school student can read it on his or her own. Or younger students along with the rest of the family can listen to the book as a read-aloud.
The activity guide has suggestions for older (middle-school) and younger (elementary) students. On top of that, the logbook is very open-ended, so that you can tailor the program to the individual students’ needs.
The following articles will help you see how you can use living books to teach science to the different age groups: