Go to something like momondo.com, throw in your dates, origin but no destination, find the cheapest return flight that isn't in Thailand and do that. Likely around 2-3000thb and will be far less work than trying to do 180 day extension or land border crossings. Can be a same day ticket if you don't want or can't afford to stay in the other country.

@James *******

No issues so far, but thanks for the warning!

I just kept it on my phone, created a folder of documents including the evidence just in case it ever comes up and I didn't have internet. Showed the visa pdf on my phone to the officer and all good.

If you want to use a sponsor make sure you have the letter signed by them, ID for that person, that they are closely related and they can clearly show financial evidence ie bank balance of at least that amount available. Ideally at least twice in the last 6 months.

But with all advice in here, will depend on the consulate and application