Two of my favorite towns along the coast are Yachats which is in Oregon just north of Cape Perpetua. The town is small and charming, but the coast south of there is incredible!! There are tidal pools right in town along the ocean that are worth stopping at for an hour or so. Tillicum Campground is a good place to stay, but not for really big vehicles. Also, it does not have a dump station, so you have to drive 10 miles to dump your tanks. But, some of the sites have ocean views so it is worthwhile.
South of Yachats is Bandon, OR, near Bullard's Beach State Park, but it fills up very very fast, so you need to get moving. The town has some lovely art pieces made of carved wood along the marina. There are some very nice shops and a couple of tiny seafood restaurants right next to the marina. Plan on spending an hour just walking around the town. The state park has full service and partial service spots and can handle large rigs.
All in all, you cannot miss on a drive down the Pacific Coast!
Almost forgot--there is a Coast Guard Museum in Astoria where the Columbia River empties into the ocean. Nice state park near there is Fort Stevens, and it also has all kinds of sites, even for big rigs.
