It takes awhile for people to understand how they work best. Many young and old writers I know spend a lot of time looking at how other writers write. I know a lot of other people's schedules. Murakami, for instance, writes very early in the morning until about 10 and then spends the day exercising, listening to music, or reading. He keeps on this schedule for the duration of working on a single novel.
Murakami does not have children.
Denis Johnson writes where his wife and daughter are passing by him. Near the kitchen normally. And, whenever he feels like doing it.
As useful as this is to know, it doesn't seem to actually make any other writer's routine easier. I've tried a lot of things including writing late at night (like Michael Chabon) and always just found I got tired and thought about what I'd have to do in the morning. I've tried getting up early, 5ish for awhile, and writing. Again, I was just tired.
But, I think I've found the way to actually really get work done.
I need to be working on 3 things at once. Then it doesn't matter when I find the time to write, I will have something to work on.
1) A first write.
2) A 2nd write or edit.
3) An edit with my editor or notes for a new novel.
When I'm wide awake and ready to go and feel the energy, I go straight to that first write and pick up wherever I've left off. Normally I read a little from one of my favorite authors, depending on genre (right now I'm editing a YA mystery, writing a PI novel, and researching/thinking about an adult 'lit' book and 2 YA novels I need to write before August). So, if I'm working on the PI novel, for instance, I'll read a page or so of a Dennis Lehane or George Pelecanos or Richard Price book. I feel encouraged reading these others writers. And it keeps me on my toes. Lets me know that even in a first write, I need to keep a consistent quality and voice.
If I'm less awake or have less time to work, I go to the edit. I read all my novels out loud at least once. Sometimes three or four times. I edit as I go through this, checking for how it sounds. The YA novels have shorter chapters so with ten or fifteen minutes I can dig through a chapter or even two and feel as though I'm making headway.
When I'm driving to the college or out walking or running, I think about the next novel. Take some notes. Consider the main concerns and ideas. And, if something good comes up, I might take an hour to do some actual writing so that when the edited novel is done and sent off, I can jump into editing the first write novel and writing the new one.
It works for me. Though I have to say it has taken awhile to figure this out. The timing isn't always right, though, which can be difficult. When I am missing a component I go back and edit an older novel, considering ways it could be done better or write a short story.
That's the way I work. I wouldn't suggest it to anyone else. In the end I think it has less to do with routine and structure, and more to do with just being able to work on something whenever you have the time.