I've been working on the syllabus for my graduate Milton class for ages. It really shouldn't take this long: I've taught five Milton courses at either the advanced undergrad or grad level over the past seven years, and I always teach more or less the same primary texts, always in a roughly chronological fashion. So what's so hard?
Part of what's hard is that I keep switching textbooks, and that means figuring out what is and isn't in each one. Some have more useful supporting materials than others, and none has exactly the same excerpts from the prose works. Moreover, a new text--without my pre-existing flags and annotations--means I spend hours trying to find the things I want.
It's also hard to pick the right secondary sources and the right number of them; I still don't have a feel for how much (and what kind) of critical reading is reasonable to expect of M.A. students. My Milton grad class three years ago was amazing, and I could've given them even more secondary readings than I did--so my impulse is to up the workload slightly from last time (as well as to replace several articles that turned out to be duds). On the other hand, my Donne grad class the following semester was much weaker and had a difficult time not only with dense critical readings but even with some of the primary texts. Since this will be only my third M.A.-level class, it's hard to know whether my first or my second was the more typical.
It's awesome having a well-designed course that's pretty much ready to go whenever I teach it. It's also awesome to design a new course from scratch. Even redesigning an old course can be intellectually stimulating. But this kind of rejiggering-without-real-redesign? Just a drag, man.