I stopped MANY times on my journey through the lessons. If I had stopped at, lets say the middle of Mod 5, I would go back to the Medium and Fast workouts for Module 4 to see where I stood. If I was nailing those I’d move along until I wasn’t and pick up from there. If I wasn’t nailing those I’d move back further in the lesson plan until I was. Basically, pick it up a lesson or two before you are struggling.
Theory/Concept if something does not make sense you can always just go back to that specific lesson where Josh covers it.
I aldo agree with the idea of learning a new song as well. If you choose a good fun song within your skill level(or hopefully just slightly pushing it) you will get you back to having fun with the instrument right away. These lessons are very fun, and amazing instruction, but nothing replaces that feeling when you are starting out and you are playing along with one of your favorite songs!
No matter how you choose to jump bank in, as long as the bass is in your hands you are off to a great start!