Which school(s) in Mexico? I've been thinking about that too.
As I recall, you are an unlimited Master and DPO?
Try the Harley Marine companies. They have recently posted afew shoreside jobs from Seattle to LA, to Houston, to NY. As far as I can tell, most of Harley's seagoing jobs don't really exist, but I get the impression that the shoreside jobs do.
I have not seen any ads from Crowley for awhile, but they often seem to be looking for shoreside personnel. Signet is another company that was looking for shoreside managers.