I’ve done a few 130+ mile rides from Manchester to see family the other side of the country with the strava auto route planner. Having no idea about the roads over that way I just have to either take a punt and go for a best guess or spend ages asking friends and relatives what particular roads are like.
In all that time it’s only sent me down one road that I was cursing it for (I think it was the A57 into Lincoln) and every time I’ve tweaked the route to avoid something that looked nasty on the map I’ve regretted it, the worst of those was adding an extra 1000ft of climbing in the Peak to avoid about a mile of A road!
Oh, no hang on, there was the time it sent me down a dual carriage way full of lorries, i bailed at the first exit and just followed the compass on the garmin until I picked up the route again a few miles later. **** that for a laugh.