If you can come to Thailand on a US passport, you will get a 30-day exemption, which you can then extend for another 30 days. You can then travel to nearby Laos or Vietnam to get a proper Non-O visa. This is often considered easier for foreigners because you don't need to show insurance, as you do with the OA version of this visa.

Yes, Pattaya has an immigration office.

Most medium to big cities will have an immigration office. If you're in a city that doesn't have an immigration office, you can do it at the police station, although I haven't done it that way. I've only done it in Bangkok.

Note that this will take anywhere from 1-4 hours in a big city like Bangkok.

You can extend a 30-day visa exemption at the immigration officer that covers the hotel where you are staying. So if you're in Bangkok, you can go to the Immigration office out at Chang Wattana, then pay 1900thb, with an application, and get the extension for another 30 days.

There is an international bus that leaves from the Mukdahan bus station every 30 minutes or so. It's like 50 baht, and they take you to the Thai side, then to the Laos side. I believe they also go to the bus station in Savannakhet, but I usually just get a tuk-tuk on the Laos side, to go straight to the Thai Consulate. That's usually 200thb or so.

Note that you can ALSO get a year-long multiple-entry visa based on marriage outside the country, at HCMC or Savannakhet. These applications do not require you to show proof of income, but you will have to leave the country every 90 days after you come back.

Also note that with an overstay, you can no longer use the fasttrak services at the airport...

She wrote it all in Thai.

The requirements for this are very lax. My wife wrote out a handwritten note in about five minutes, and they accepted it. It needs both your names and it must say that you're legally married and the documents are correct. Then she must sign it. The example posted above from Benjamin Hays is sufficient. Don't stress too much.