Here are some random thoughts on the issue of trying to find time/energy to write while teaching four classes.
Since none of us are inexhaustible, it’s tough to strike a balance between the energy we put into our own writing and the energy we put into our teaching. However, I think there’s a tendency to unnecessarily separate the two when, in fact, each can assist the other. Put another way, if we sharply distinguish our writing selves from our teaching selves, I think it’s actually much more likely that we’ll run out of steam and feel like we don’t have enough time or energy for either.
Good teachers are invested in what they're doing—not just because it’s better for the students but because in the long run, it helps us by creating a more congenial, less stressful classroom environment. Likewise, writers aren’t just writers when they’re sitting at their desks, but also when they're waiting in line or stuck in traffic. If we're going to draw inspiration from the news, or mythology, or our own imaginations, why not draw inspiration from the 75-100 human beings we see 12 hours a week?
Our students (good or bad) are part of the world we write about, so teaching them is actually (in my view) a chance to observe a lot of people of different beliefs from many different backgrounds, a lot of stories, and put all that raw data to good use. It’s a chance to make our jobs as writers EASIER by getting some of the reflection work done before we actually sit down to write. I don't mean that in the sense of being a literary vulture, fiendishly waiting for a student to give up juicy details of a trouble past so we can steal them for our own writing. I just mean (as cheesy as this sounds) allowing our students to broaden our understanding of our society, our country, our world, which in turn can greatly inform our own work as academics, since our own work is probably striving for some kind of elucidation, anyway.
Besides that, being writers ourselves sadly doesn’t add more hours to the day, so it still comes down to basic time management. Setting aside huge blocks of free time probably isn’t going to work since those huge blocks of free time probably don’t exist, anyway. Instead, write when you can, whenever you can, whenever/wherever you can find the time and energy, even if it’s just jotting down a thought on a note card (or a Smartphone) or more likely, just thinking about our stuff and going over lines and thoughts in the car on the way to work, or asking ourselves while addressing a student’s question, “How does this issue reflect my own thoughts and research?”
If it doesn't, maybe it should. Just my two cents.