Gimli's Route to Rivendell

[Inziladun]

Originally Posted by Tuor in Gondolin

Related. What would be the way messagesmight be passed between
Moria and Erebor? By bird or dwarf? Perhaps passing men,
or, given the length of such a journey, dwarves taking messages to the Beornings
and then having them give it to a passing traveler to get to
Dale? And would it be a one- or two-way message sysem?

I can't see Dwarves passing important messages meant for other Dwarves in the hands of one of an alien race.

The ravens, such as Roäc son of Carc could have been an option. In The Hobbit, Roäc said his "people were few", but the ravens lived for more than 100 years, it was said, and under the protection of the new Kingdom Under the Mountain their numbers might have increased.

Then again, if that was the case, I'd wonder why Balin and Co. wouldn't have had a raven or two with them at Moria. If they had, the fate of the colony should have been brought back to Dáin by them.

Originally Posted by Tuor in Gondolin

Or perhaps the best, surest way would be to use rangers(both rangers and dwarves could be of service to the other
and want to keep on good terms).

I wouldn't think that likely due to the fact the Rangers seem to have mostly confined their activities west of the Mountains. Crossing the Mountains to act as errand boys for Dwarves also seems a bit below their pay grade, and would further have reduced the number of Rangers able to guard Bree and the Westlands.

Maybe after all it was just physically journeying Dwarves passing back and forth, possibly not even going all the way to Erebor or Moria, but meeting at pre-arranged places and times.
When the Moria lot didn't make a rendezvous 2 or 3 times in a row, that could have given Dáin a hint that they'd run into Durin's Bane and were beyond help or hope.