Change of plans! We decided to stay put for one more night. It turns out that the castle we were hoping to visit now charges a €10 fee to overnight there, and it's not that important to us. So the only other option in that area was beach camping at a restaurant. We decided that if we are going to beach camp, we've got it pretty good right where we are!
And with some rain in the forecast, we didn't want to be stuck (literally!) in soft sand or on a muddy road.