As far as I know I stuck to the route - as in I just downloaded the file and stuck to route , I went wrong at the very beginning and couldn’t work it out ( just left Holyhead and lost on a golf course somewhere ) apart from that it was easy to follow - I even paid the troll ! As I only did it once I couldn’t tell you if there’s a better way , I can say that one hill seemed brutally unnecessary as it seemed to go out your way to do it