I work as a langauge teacher for immigrants, many of them with very little previous computer experience. For us, the length and complexity of the main/middle part in the course really is a problem.
The students have to scroll a lot, and quite a few of them don't even understand that they have to scroll, and so they end up seeing only half the material in the course.
What I suggest, is a possibility to organize the sections as tabs, and in this way keep the course within one screen. If, for example, you chose a "weekly" outline, each week could have its own tab.
I have no programming experience, so I don't know if this is feasible, but I do believe it would make things easier for us.
All the best