Re: I use a map.
Using known points of reference to trace a longer route is called "piloting", and is one of the two forms of navigation used since navigation was invented (the other one is called "dead reckoning" and is how ships discovered new places by crashing into them before the advent of the chronometer and an established meridian baseline against which to calibrate it).
It has been around for centuries, and you've been doing it since you could walk. Neat, eh?
No routers needed.