Eknath Easwaran was one of those who created such a retreat. I've read one of his books.

https://en.wikipedia.org/wiki/Eknath_Easwaran

https://www.bmcm.org/about/about-eknath-easwaran/

https://www.bmcm.org/about/easwaran-bio/

https://www.bmcm.org/about/about-bmcm/