Here you see a POI collection, below a mixed map with POI Collection and a planned route.
I did wrote a lot about this
topic. Did test a lot of tools.
What is helpful, depends a lot on the tools you will use later for navigation itself.
Above are Screenshots out of my Google`s My Maps. It is a good allrounder in my eyes - which allows collaboration with others. Allows to share your route and POI to others. And it allows too export and import the POI and Route to your Navigation Device.
If your Navigation Computer cant import KML or GPX Files you may find this way less useful..
I mostly enjoy travelling without a given route, but I love to have a set of Waypoints, to see what is nearby.
But you asked too for a way to find dirt-tracks and handle them. Give the App wikiloc a try. It is just for that - to find driveable dirt kategorized by vehicle category.
Surfy