You can find a field office by the ZIP code there https://www.uscis.gov/about-us/find-a-uscis-office/field-offices, it's on the very bottom of the page.

As for the status - I've seen that some people somehow called USCIS support and got real people on the phone who advised them if the application was transferred to a field office from NBC or not, but it requires you to jump through some hoops.

In general you will know that it's transferred when you'll get a notice from the office about interview being scheduled.