Hi John - thanks for the suggestion. That sort of feature would need to be delivered via an app I think. We have a route tracking app on our Feature Requests list already (number 25), so anyone who is interested in it can vote for it there.
It would be great if I could just turn on a function to record the route I'm currently doing and then save it as a route. That way when I'm exploring I can replicate the route at a later date.