We have not stayed in many of the State Parks on the OR Coast but we have found most of them to be more sandy than grass. Our new favorite is Winchester Bay RV resort and there is quite a bit of grass at the sites but the big dog walking area is hardpack and sand. They do have monthly rates and I look at what I have on file for prices. Hold on for a minute...
Well the DW has the current rates and she is school clothes shopping with the DGS. My old prices were from about $250 to $575 a week. I seem to remember something like starting at $300 now. There are four price levels for sites and NONE of them are undesirable. There is a Rec. Cent. with big screen TVs for your use or rental. Florence is less than forty miles away, Newport is another half hour and are not to bad a drive. The Light house above the bay is a great museum now, there is an oyster packing plant in town as well as an oyster farm in the mouth of the bay. It is a great point for travel for 50 miles either side of the coast.
Scope all those mentioned here online and you'll find something for all you needs.
I forgot to mention that at the public dock on the Alsea River at Waldport the crabbing does not require a license. You can rent rings and buy bait at the head of the pier as well as have your catch cooked and cleaned, if you want they will also put your catch in a bag with ice to take home.