I didn't know the area, but I looked at maps online and thought that it wouldn't be that tough of a hike. Google maps showed only a few spots of green in an ocean of suburbia, and the county website measured the park in acres. Besides, it would be mostly flat.
Well, it was mostly flat.
We started from the Bound Brook train station, walking on local roads to Washington Valley Park. Then we did a little loop. Then another little loop. Then we headed as far west as one could go in the park system. And by then we were at 14 miles, but we still had to return to the train station. By the time we finished, we had clocked in at 20.1 miles - my third-longest hike.
The park itself was, as county parks can be, surprisingly pretty without being spectacular. It's wasn't the kind of place tourists would drive across country to see. But it was nice, with two lakes and a (man-made) waterfall; on our hike the park benefited from the added boost of wildflower season.