We stayed at Cape Disappointment for the second time last summer and took a drive over to Ft Stevens to see what it was like. Waaaaaay more crowded. At least that's how it felt, and we weren't even towing when we went through. And if you are leaving at the time that the other campers are and need to use the dump station, better plan on an extra hour getting out of the park, or go around out the back way. There were actually rangers out directing traffic so people could get out of the park.
Cape Disappointment, on the other hand, has more open space. You are right on the beach and have full hookups.