Nerwen -
.
I was thinking about this earlier, but as I had nothing concrete to back up my guess and very little knowledge on it overall and because I did not think it's the correct answer I did not say it. But now that both
Nerwen and
Might have been wrong I fail to see any of other options (except for something about as silly as what
Nerwen just suggested
), so possibly, would the fastest route have been
by the sea from some Gondorian port to Grey Havens?