Staying out at the beach until sunset wasn’t a bad idea. I knew it would get dark after that, but I had time to get back to the campground.
Except that I had the notion to take a different route back. Not so great an idea, in retrospect.
I thought it would be more interesting to hike north along the beach and take another trail back across the dunes, then back south through the woods. So there was a hike along the beach, as it got darker. I could still see my way easily, though.
I finally got to the trail back, and after climbing the dune it took me into the woods, where it got darker. The trail also descended rapidly, and eventually reached a spot where the day’s rain had collected. I’d made my way around a large puddle on the way to the beach. This was no puddle. It was hard to see through the dark, but as far as I could see ahead, there was water covering the trail. The woods were thick and there was no sign that previous hikers had blazed a spur around the obstacle. I was forced to backtrack.
There was a third trail nearby that I could take, but at that point I was getting tired (yeah, I’m out of shape) and I didn’t want to risk another dead end. So I hiked back over the dune, back down the beach, then back over the dune again to the campground. And through the aforementioned puddle. By the time I got back I needed the flashlight, and had been out in the day-use part of the park for an hour past “closing”.