The Lands End to John O'Groats thread

A quick pre-tour update. We're heading off at the weekend, largely following the Cicerone 14 day route. The overall route outline is non-negotiable since we've pre-booked all accommodation along the way. (With just a couple of minor detours to stay with relatives in Somerset and Liverpool.) BUT in checking on the details of the Cicerone route from Carlisle to Gretna Green, I couldn't help thinking that the Google recommended cycle route, besides being a couple of miles shorter, seems a little more pleasant. Cicerone has you going straight up the A7 and into Gretna via Longtown, whereas Google sends you further West along what looks like a more minor country lane, then alongside the M6. So a couple of queries, one specific, one more general:

• A7 or Google route?
  
• If anyone has followed/knows the Cicerone route, would you recommend any particular alternative routes along the way? Is it worth comparing Google alternatives each morning? I've got Google Maps on the phone, but also have the Cicerone route as daily GPX routes on the Ride with GPS app (plus the paperback book as back-up), so navigation won't be an issue.
  
  

n.b. W.r.t. preferred routing, I've definitely got a higher tolerance than my girlfriend for cycling on busy roads and being blown around by lorries. For the sake of harmony, "we" would prefer to stick to quieter roads if they're going in roughly the right direction! :-)

Ta!