Restroom

Yes this building house the restrooms. They are located in the rear of the building facing away from the parking lot. They were clean, but pretty basic. They did the job and that's what you want.
But everyone leaves off the other half of the building. The front side facing the parking lot is a little gift shop and snack bar. They had a good amount of souvenirs and such. But what I liked more was the little snack bar. The ladies were very nice. They had basic hot dog and hamburger type food. But for example: the hot dogs were beef hotdogs. They were good size hotdogs. And they tasted quite good for a snack bar. Best of all, unlike most snack bars in tourist locations. This snack bar provides decent food at a very reasonable price.
We had lunch for two at this snack bar, for less money than one beef large dog would have cost us at the Hearst Castle just days before. So yes, they were very reasonable. And yes, Hearst Castle was very expensive.
So I recommend trying the snack bar and having a picnic lunch at the park. We really enjoyed it.

Basic industrial amenities with flushable toilets.

Its a restroom what do you expect