Don't know what involved in US or UK theory for PPL but a weekend course might be a bit ambitious.
In Oz we have the Basic Aeronautical Knowledge for the GFPT (old restricted PPL for carrying passengers near the field) this is basically aerodynamics and engines with no nav, met or operations.
Many years ago I did a series of BAK courses with IIRC the then standard 2 hrs one night a week for 6 weeks and following requests ran it as a weekend course and it was a disaster. The underlying problem was that to cover the syllabus too much in the way of new concepts had to be imparted without time for the brain to digest them so that by the Sat evening I was looking at a lot of stunned mullets. It was only sucessful in the case of:
a) Students who had attempted to do the whole thing from a book, had most of the concepts and only needed help on a few points.
b) A introduction for one student who was rather bright, passed but I had to give him some revision a couple of weeks later as he had basically forgotten the lot. It went into short term memory but was not digested into long term memory.
Regarding learning from the books it helps if you have at least two to cross check and clarify points. An example of this is my wife who did an Oz ultralight course a year ago and I thought it would be just as easy to get the GA BAK done which covered the AUF requirements as well. So we go and examine (IIRC) 3 texts which cover the subject and return with the Thom book (on the basis that she felt it explained things best for her) and a few sample exams.
She disappears with the book and comes back with a query about a answer to a question from the problems at the end of the first chapter. The answer was correctly given as camber but neither of us could find any mention of it in the chapter. No doubt any book will have similar problems.