My mother is disabled and lives with me, but for years before that, I'd drive to her house most every Sunday for dinner and a movie. I lived in Orem, UT. She lived in Salt Lake City. I hadn't discovered podcasts yet, so I spent most of that time listening to music. But more importantly, I spent those 45 minutes, both ways, twice a week, grinding on plot. Drilling down on story problems. Digesting the writing I'd done that week. Planning my writing for the next week. Just working through those mental cycles necessary to work out the issues.
I've joked before how there have been periods where I quit writing on my drive home every night after Writers' Group, only to recommit and figure out my way forward by the time I arrived at my door. Long commute. I have a 25-minute drive to work (35-minutes in good weather when construction starts). Long commute. There are times at work when I just can't stare at the screen anymore and I step into the big conference room and stare off at the big NSA complex off on the distant mountains (I've probably been flagged). Not a long commute, but a few minutes when my subconscious sits idle.
We talk a lot as writers about the importance of butt-in-chair time, and I don't want to discount that, but just as important is that time when you're not working on writing...when your brain can process what you've done and what you're going to do. For me, it's the commute. For you, it might be house cleaning, or yard work, or gardening, or building that shed out back, or pulling cable because your significant other has the same reaction to exposed cables as most people have to snakes. Maybe it's running errands. Maybe it's paying bills. Maybe it's organizing your sock drawer. I don't know, but your conscious mind frees up and can work on the product at hand and suddenly your realize, "Oh. Hey. My plan is super convoluted at the end because it needs to be for it to work out, but the person who made the plan didn't know it needed to be convoluted. She should have made it simple. I need to come up with an excuse for her to have foreseen all this. Dammit."
I'm an outliner, a pantser only by necessity. Still, my favorite moments are when I walk into the climax and realize the hero's plan won't work and that my whole outline for the ending goes out the window, because I don't stop writing, I just start writing desperately, and I think it comes across in the character's desperation. But I don't recommend that for the weak of heart. I suggest figuring out that plan doesn't work about two months before you have to write it, so that you have two months of showers and drives and long meetings where that one guy (you know the guy) is talking for you to figure out what the real plan should be.
I had my first gray hair at seventeen. I started writing in earnest at sixteen. You do the math.