Thanks George and Jim. 
George, yes, it is sometimes difficult to decide on the exact exposure, but that is something that adds to the mystery of the shot. Full moon is surprisingly bright, once your eyes adjust to it.
Technically speaking the horizon is blurred as it is outside the depth of field for this photograph (at 100% it is visibly blurred). Obviously the shore and clouds blur more due to the movement, but it's all as nature provided, and the timescale did the rest!
Jim, I always use manual focus. In this case I had nothing to focus on (manual or otherwise!) at the hyperfocal distance. The next best thing would be to use the distance scale on my lens, but it has nothing marked on it past the 3 feet marker, then only a small gap to infinity. That's why I'm going to do some test focuses at pre-measured distances, then note their position within the unmarked part of the distance scale on my lens. 
Mike