Create a transparent map with a track

My question perhaps is OT but I could not find info on this subject.

I own a nuvi 205 and I’d like to be able to load some map. I know how to to this but since my nuvi can’t handle routes it is difficult to follow a path different forn the one suggested by the nuvi software.
It would be interesting to be able to create a transparent map with my own path. Something similar to the contour lines in the wiki. But I need just a track that can help me keeping my path.

Thank you