The library: It’s nothing sexy but I’ve always had luck going to the library and grabbing all of the books off the shelf on the subject I’m learning. I then sit at a table and quickly scan through the stack. After finding the ones that seem the most valuable of the lot I take those home and work through them. I was lucky to live in a major city so my library had a ton of content.
On your note about carrying a few notebooks: I was in this same boat. I carried a paper planner, a notebook for notes and lists, and another one with graph paper for projects (wiring diagrams, building floor plans, etc). I’ve been using a Midori travelers notebook for the last year. It’s essentially just a nice piece of leather that holds inserts (think field notes type notebooks). I have 3 inserts in mine that cover those areas and when they fill up I can replace each one individually. I’m loving it and the leather looks really classy.
For automotive repair the 3 best resources I’ve found are youtube, buying a Haynes repair manual, and the ALLDATA website. Youtube has videos for doing most things on your car/truck, a Haynes repair manual walks you through a ton of basic to advanced procedures (it pays for itself), and repair shops use ALLDATA. It’s more advanced and a bit less intuitive but a great resource. I get it free through my local library which is great too!