Trade and traderoutes in M-E

[Tuor in Gondolin]

About the third leg of the trade routes (Fornost to
Gondor/Calenardhon), until c. 2000 of the Third
Age it would seem to have had the potential of being
not only a sort of Royal Road (like the Persian road from
their capitals through Asia Minor) but also a path of
commerce. Indeed into the Second Age also the Noldor in
Hollin and Moria dwarves would probably participate in
some form in trade and travel.

And continuing trade and travel potential is seen in Butterbur
observations after the War of the Ring.

It all comes from those newcomers and gangrels that
began coming up the Greenway last year, as you may remember;
but more came later. Some were just poor bodies running away
from trouble; but most were bad men, full o'thievery and mischief.

and Gandalf's prediction:

...the Greenway will be opened again, and his messengers
will come north, and there will be comings and goings, and the evil
things will be drivenout of the waste-lands. Indeed the waste in time
will be waste no longer, and there will be people and fields where once
there was wilderness.

There are several things here. One, who were these refugees and where
did they come from? Dunland? Perhaps a few. Rohan, maybe a handful of
Wormtongish- but doubtful. Perhaps people from some areas of South
Gondor going through Anfalas?
Two, Gandalf's comments suggest not a naturally barren land in Minhiriath
and Enedwaith but one almost unnaturally depopulated (shades of the
Dust Bowl?) Perhaps some New Deal CCC (Civilian Conservation Corp)
replantings and soil management was called for

The point is the basis for a trade route is there for a good bit of the Second
and Third Ages, and even in a form of Dark Ages for the region (including not
seeing to upkeep of fords) you'd think it would be marginally kept open by
entrepreneurs. Btw, had tobacco use spread to Gondor (perhaps Thorongil
brought the vice there ).

And then there's that potential sea route, Forlindon to Pelargir...