How often can I re-enter Thailand to obtain a 30-day visa exemption, and what are my options for staying longer?

You might clarify your passport, your name is Korean but I'm guessing from the 30 day exemption you aren't a South Korean citizen?

If you know you are getting a work visa in February and aren't Korean, extend your current exemption for a further 30 days. Then presuming your current one is the first in 2019 you can do another and that will get you through to next year, maybe enough until you get your work visa, but if not you can do another in early 2020 as the "two" resets on Jan 1.

Alternately try for a 60 day visa somewhere like Vientiane, if it is your first you have good chance with it and if they do reject you you can fall back to a visa exempt entry.

If you did have a Korean passport that would get you 90 days stamp with no visa.

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@Jeremy *******

said you can get TWO 30 day visa exempt entries by land in a calendar year (Jan 1 - Dec 31).

Here's a thought, you're on a 30 day visa exempt entry now, so go get that extended by 30 days at the immigration office for 1900baht, THEN go to a thai consulate in another country and BUY a single entry tourist visa ? That'd get you stamped in for 60 days and you could extend that by 30 more days at the immigration office.

Doing that buys the time you say you need until your'e going to get a 'work visa'.

How do you mean that you're supposed to get a work visa in 2020? If you give the group as much detail as possible you will get the best advice

2 land border crossings per year... in theory unlimited visa exemptions via air crossings, however the consensus theory is the I/O’s will frown on it after 3-5 Out/In’s in a row...get an SETV or if you qualify a 6 month METV