Word-of-mouth leads in Boston - any advice?

Two small Boston employers told me they are hiring but have not posted yet. I have been trying to stay organised about it. They prefer people who can start within a couple of weeks. Should I visit in person?

Visiting in person worked for a trades job. For office jobs, email was better.

A short email with two sentences about what you can do and your résumé attached worked for me. I followed up after a week.