Be wary if following someone else. I have been led astray a number of times.
Agreed: On London-Edinburgh-London I'd made my own route which avoided some climbs I didn't want to do as I was carrying a previous injury, instead taking a more circuitous way. Lo and behold, coming out of Louth southwards, there were four riders behind me. None had a navigation system or map and they'd just followed others all the way round. In the 100 hour group they were on the time limit and just hoped that by getting someone to follow they would make it.
I
was nice and towed them
my way round until it led back to the correct route, losing about 15 minutes in the process as they were slower. And they never did make it in 100 hours whereas I did.