Just a caution here....this thread is getting off track, into (forbidden) union/ non union areas of discussion.
Obviously, a man looking for work in a new town will have his choices very strongly defined by whether or not he belongs to a craft union. Nor is union membership something you can don or remove like a new jacket!
As a union member, i would expect the local to be a resource for me, regarding the local market.
Absent that resource, there is no quick way to "separate the sheep from the goats."
Another item, so far overlooked in this discussion, is that it is rare for a construction worker to stay with an employer for any extended period; he follows the work, without regard to who the actual contractor may be. That's why we're called "Journeymen."
Now, I do have another suggestion....why not visit city hall, and have an informal chat with the inspectors? They just might point you in the right direction.
