You can't generalise like that. I've tried it here in the Limmat Valley and some people know it, some don't.

Hi I am currently travelling in Brittany and it works perfectly on main roads and side roads there I don't think it works for mountain biking and hiking trails Greetings

It has a compass mode that will guide you roughly in the right direction even if it doesn't have road data for the routes you are travelling. But you can also simply import .gpx files