I've spent some time with Merton. I think I had a false idea of him, to the extent I had any idea at all, because I associated him with pacifisms, civil rights, and things like that, and thought of him as some kind of hip poet-monk. He was that, I'm sure too, and his reaching out to Asian religious traditions is probably interesting.
In his book on St. John of the Cross, The Ascent to Truth, punished in 1951, he sounds a lot like Pope John Paul II on the same figure, in the future Pope's 1949 treatise: both emphasize the Thomistic, rational and orthodox quality of Saint John and his value to protect against "false mysticism."
Although they are both poets, neither approaches San Juan as a poet in the least. Merton's first book of poetry is called Strange Islands, a phrase from the CE (repeated twice.) So that's next on my list of things to read.