If you want to use gps there are constantly upgraded Oil service and logging road not found on regular maps. These can be bought and dl into your gps no way to mark on a map unless you have a plotter printer due to size of area. i get them through surveyor friends they also have nice things like mineral deposits elevation cross sections, water sources (including tidal pools with time they spring forth) learn them mark them which season they are passable. carry a cb radio for updates and any closures.
If you know the road you can even find fuel reserves if you know what to look for. These roads can not be done in a city vehicle you should have a 4×4 with chains and winch.