What do I need to provide and do to apply for a marriage visa from the USA for Thailand?

Just return on a visa exempt stamp, then immediately apply for your type O extension, Thai wife. I assume you already have the bt400,000 in your Thai bank account. It's a pretty lengthy list of documents you need for the one year extension, but if you keep copies of everything, then in future years everything is the same, except updated bank details, and new pictures, unless you move. If you apply in the US, then you need copies of your marriage license, and registration document. A copy of your wife's Thai ID, and I believe a copy of the housebook she is listed in. If you do it that way, you'll get a 90 day entry stamp. Go to immigration with your wife and get the list from them of everything you need for your 1 year extension, and anything not listed that they tell your wife.