I've routed the whole trip using MyCycleTour which I assume routes you using the best route for a bike. Much the first leg on the A81 from Milgarvie. It looks a good road to me but maybe others know better. Are we totally married to the Sustrans route? If the roads are not actually dangerous, I'm easy which route I take and I'm not in love with MTB type trails. I've ridden Sustran routes in the past [one near me] and they are not always the best IMO, if you are not on an MTB and we 've had a lot of rain/mud this summer. Sustrans seem to take funny diversions to avoid perfectly reasonable roads at times. I don't see a problem if somebody [yea, okay, maybe me] wants to take a different route and we meet up somewhere even if it's just at the hostel. I'm more bothered about the weather than the traffic at the moment. How bad is the traffic situation on alternative roads?