Agree with Tim...leave time for "Marion" during your Kittansett visit...it's a hoot!
If you have to choose between Eastward Ho and Essex County, I think you'd prefer the former. I know I did, although Essex is very good, as well. Eastward Ho is "special", in the words of the person who turned me on to it.
Let me also throw George Wright Municipal into the discussion. As the only person on the planet in history who played both Myopia Hunt and George Wright on the same day, I think you'd be quite impressed.