Hi Herm,
Welcome to the Forum! It looks like you are a serious and focused student,,,LOVE IT! You have some great questions, and as a longtime student and friend of Pebber (2008), I can definitely provide a little feedback I hope you find helpful:
I would focus the majority of your efforts on the basics (Module 1, for example). However, students are encouraged to post videos (NOT too long; 1-2 minutes is fine) of themselves running through items in Module 1. This way, we can give you feedback, but most importantly, Pebber will be able to weigh in and see where you are at. Remember, he's been at this for 35+ years and knows his stuff; no other way to put it. Assuming you are a paying student, Pebber will assess your readiness in terms of proceeding through each consecutive Module.
As far as the YouTube videos,,,,DIVE IN! Even though you want to concentrate and focus on woodshedding what your current Module dictates, it certainly does no harm to supplement this by checking out any of Pebber's YouTube vids.
The important thing is to have FUN with this, but I do advise that you take Pebber very seriously in terms of any advice he will be giving you. As long as you prioritize the current Module you are working on AND can manage your time effectively, there is no reason why you can't explore other areas in Pebber's system.
Remember: We are here to help you!!!