To find Fort Stevens, take US 101 north from Seaside or south from Astoria and turn toward the little town of Warrenton. Excellent signage will direct you toward the campground or the fort itself.
If the state park is full, or for a different camping experience, try the KOA across the road. They offer cabins and RV spaces, as well as semi-sheltered tent sites with small roofed areas. The KOA is perfect if your idea of camping includes a swimming pool, a hot tub, wifi, and a gift shop. There is also a simple restaurant where you can begin your day sitting next to a stranger, tucking into those large, rubbery disks so often sold as pancakes. They are included with your camping fee, so eat up. This is ballast for your activity-filled day at Fort Stevens.