Google Maps has a new(ish) trick: directions for walking from place to place, rather than traveling by car. It’s unlikely it was intended to cover 400 mile trips between Glasgow and London, however, and the suggested route is, at first, somewhat alarming.
This reminds me of an old routing system I had on my first PowerBook, which covered all of Europe. In mere minutes it could calculate – with split-second precision for the journey time – the optimal route from Glasgow to Venice. By bicycle.
Since the average speed of a ferry is pretty good, it took ferries wherever possible, starting with Troon to Larne. It then struggled, rather, to work out how to get from Larne to Dublin without taking the motorway, and mysteriously added a loop around the perimeter of Northern Ireland before striking out to the republic. From Dublin to, I believe, Cork (a phantom ferry which I doubt exists, though I dare say one could arrange passage on a coaster if necessary), Cork to Swansea, …
Fifteen days (eight hours, thirty-seven minutes, and twelve seconds) later: Venice. Via Morocco.