Your employer getting the Work Permit (from the Ministry of Labor) can range from 1-2 days 4-5 days to 7-9 days)...depending on jurisdiction and other factors.
With competent employer staff or contractor getting the one year extension of stay (after getting the B Visa 90 days and WP) should go smoothly enough.
With a WP.3 Application / Letter the person will have to go to a Thai Embassy / Consulate in another country (usually a neighbor country) to get the Non Imm. B 90 days.