This has to do with part of my own church experience.Here, I will add to that point. Why do I conclude Titus most likely planted Troas?
On the one hand, imagine a small leaderless congregation in turmoil, waiting for direction from an outside worker, without complete agreement among the body members as to whether we trust his authority at the moment...
On the other hand, imagine the outside worker, far away, far removed from his last visit, unsure how many saints might still be 'in his corner', if anyone...
Now, imagine the worker has to strategize HOW to send this group THAT particular letter... and not only strategize how to SEND it, but how to FOLLOW UP on that sending.
(I'm going to keep saying "imagine" because this is so foreign to most church experiences. But it isn't to me.)
Imagine that the dynamics of such a group are in flux, and that Paul knows they may very well need a good deal of UNSUPERVISED REACTION TIME, *after* reading the letter, before the group - as a group - determines what its substantial response to that letter will be.
Got all that? Now...
Paul has to get the letter in there, with a gracious and skillful carrier. Then the carrier(s) need to move on. Then Paul needs to WAIT... before arriving himself to find out whether a positive result has occurred AND has *stuck*.
So, why does Luke go ahead?
Two reasons. One, because this particular group mission from Antioch was headed further on anyway. And Two, because the Galatians needed TIME to react, to reflect, and to settle into their corporate response to Paul's letter. And Galatia needed that time to be theirs *as an unsupervised group*.
And don't say they had elders. A lot of those elders got Judiazed, so that ship had sailed. (More on Paul vs. Barnabas & elders is here.)
That's why I believe they set up a rendezvous location. No point in going back. There was a mission ahead.
Btw, I actually think this was when Titus (and Luke) planted Troas...
(1) First, as stated, because I believe Galatians 2 places Titus at Acts 16:10 (as well as in Acts 15).
(2) Secondly, because Paul told the Corinthians he expected to find Titus at Troas.
(3) This statement (2 Cor. 2:13) came about six years after Acts 16:10, a span of time during which we know Luke had remained steadfastly with the new church Philippi.
(4) In 2 Cor. 7-8 & 12, Paul describes Titus as being experienced in doing the work of an apostle.
(5) In Acts 20, Troas seems to be doing very well, as (presumably) as has been Philippi, up to Luke's departure. This was true of both Corinth and Ephesus while Paul was present. This pattern would seem to suggest Troas had also benefited from a period of long-term ministry.
(6) Aside from the brethren in Rome, where Paul had not been, Troas is the only church Paul visits in Acts whose origin Luke does not relate. Since Luke (for whatever reason) always omits Titus, and given the five points above, this seems likely not a coincidence.
Conclusion: Titus and Luke visited Galatia, delivered Paul's letter, testified about Acts 15, left Galatia, went on to Troas, proclaimed the Gospel and planted a church. Then, after Paul, Silas and Timothy arrived, Titus stayed in Troas while the other four went on to Philippi.
In the year the Galatia disaster resolved, upon realizing their hastily appointed elders had proven utterly useless to settle their crisis, Paul resolved to keep planters with new churches for as long as possible.
And so, Paul's ecclesiology continued developing.
Amen, Lord. May ours keep on (or begin) developing, also...
Appointing Elders: Barnabas vs. Paul