Nicely done, and a good write up. That loop is more or less my default loop as my Mum lives in WK, and I live in Bebington. The route you took is reasonable, and keeps you off road as far as is practicable, the only thing I would mention is that it is far safer to go around the roundabout for the new ferry bypass and on to cambeltown road that way than it is to use the cycle crossing, simply because of the blind bend and the speed of cars coming off the bypass.