Is Walks and talks of an American farmer in England (Part 1 of 2) in the public domain?

Yes. "Walks and talks of an American farmer in England (Part 1 of 2)" by Olmsted, Frederick Law is in the public domain in the United States, which means it's free to read, download, and distribute. The full text is available free on Lex with no signup required.

Is there a free audiobook of Walks and talks of an American farmer in England (Part 1 of 2)?

"Walks and talks of an American farmer in England (Part 1 of 2)" does not currently have a free audiobook available on Lex, but you can read the full text for free online.