Take a look at the course book for any Junior College and see if your library has it. From my experience, 1 textbook lasts 2 semesters or 1 year.
Beginner courses pretty much universally stop before modifying noun clauses with a verb. If you can construct a sentence like "The buss that ran the red light had it's door open." Then you can just skip to intermediate. If you can use causative and passive verbs, then you probably don't need to take a course at all.
If your a total beginner and wondering if classes are better than self study, then I would have to say that there is no comparison. I would estimate that a beginner course is at least twice as fast as self study, if you are diligent. I took beginner courses, but managed to skip intermediate, due to unfortunate circumstances. However, with diligent study I finished the intermediate textbook in half the time it would have taken me to take the course.
If your doing self study, make sure you get a real textbook. The garbage they market to self-learners boggles the mind. Don't use any book you would ever find at a Barnes&Noble. This forum is full of suggestions. If you don't trust random people that are probably perpetually at the beginner-intermediate stage, then trust the textbooks the local colleges use.