@David *********
as mentioned, 30 day extension is gotten at immigration, not at the border. If staying in Khao Lak this means a trip to Phang Nga.
If you want another 60 days exempt entry via Ranong, rest assured that the IO’s there will not stamp you out if they are not willing to stamp you back in. They won’t let you be stuck in limbo between the two countries.
And the pier btw is clearly indicated on Google Maps:
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