The novel I'm currently working on, a paranormal/romance/ thriller tentatively titled Saving Atlantis, is going through that process. I'm starting in SW Wisconsin and driving to Orlando, Florida.
To continue the metaphor, for the first 45,000 words or so, I was on the interstate and headed south and east. The words flowed, the wheels turned about 65-70 mph, and progress was good. And then I stalled. I came to a place where I had to choose a direction, but there were no signs that really pointed me where I wanted to go.
I took an exit ramp and drove tentatively on side roads for a while, heading generally in the right direction but not making a lot of progress.
When writing Prophecy of Honor the road was smooth and there were no detours. It was a shorter trip, like Wisconsin to SW Nebraska. I just got onto the Interstate and drove till I got there. But Saving Atlantis is much longer and more complicated. I had the climax pretty well figured out, but how to get to that climax—which exits and turns to take to get to my specific goal in Orlando—wasn't clear.
But I spend a lot of time thinking about the trip. And this week I found the road signs! I have a much better idea now how to get where I'm going. I'm still stuck on the back roads for a while, but once I can get back to the highway I'll be able to make some time.
Somebody will indeed save Atlantis...in fact, two somebodies, working each alone but in concert. And neither one will be the main character. He'll have other problems. Or, rather, he will be a problem for others.
Ah, yes, the trip is looking much better than it did last week.