I believe the 24 week plan is the same as the book but it uses TrainingPeaks (TP) as the tracking/calendar medium.
An alternative to using TP + 24 week plan is to use the TftNA log book:
I found the learning curve w/ the log book much more gradual vs. TP.
However, at the end of the day you can do/learn/track more with TP. So it just depends on where you’re at and how much time/effort you want to put into learning a new tool.