If this is an American marriage license, it will need to be translated to Thai first. Then registered at the Thai Ministry of Foreign Affairs, then submitted to the Amphur for the Kor Ror 22. Can't open a bank account until all of that gets completed once here.
If you plan on being here less than 60 days, just a valid passport (6 months remaining) and a scheduled return flight. If you show up as a tourist and start bouncing across the border to reset your 60 days, yes, you will be met with resistance with immigration. That is who the Thai government is targeting, those taking advantage of a loophole. They claim that if you are doing this, you need to search and find a visa that matches your intentions in Thailand. My Visa is good for 90 days with the option to extend another 60 and extend another year after that. There is more fine detail along the way but that is the jist of things.
You get 60 days visa exempt as a tourist. Just need a passport with six month validation remaining and an onward flight (return flight) when you board your airline. That's it. No visa required as a tourist. You will not be reimbursed.