I don't think it is easy for Thai women. Having said that, I took my better half to Peru a few years ago and as we had to change planes in the USA, and stay in the airport, she needed a visa. Apparently, the US airports are easy to walk out of even if you are a transit passenger.
She had a copy of our marriage certificate, and I wrote a letter for her to show the interviewer at the embassy that while she is a housewife I guaranteed her insurance and any costs. She also had an onward air ticket to show (and return to Thailand). It was all very quick.
Let her take along all the documents that others here have suggested and tell her there is no need to be nervous. The staff are very friendly.