For the first eight verses of the poem, the speaker stays out of our way. He's just a stenographer or court reporter, dutifully keeping track of the conversation between the joker and the thief. He only makes one teensy addition to the conversation: the word "kindly" to describe the thief's tone. At that point, we realize that this song is a story after all and not just some word-for-word transcript of a conversation.
Similarly, the last four verses are just factual descriptions of stuff that happened, but at least we're hearing it directly from the speaker's mouth. He's not into flowery images or descriptive adjectives. The most descriptive word in the poem is probably "barefoot."
We also suspect that it might be Backwards Day for this speaker. He had a jelly and peanut butter sandwich for lunch, followed several hours later by cream cheese and a bagel for breakfast. But seriously, he tells this story in reverse order, starting with the dialogue and ending with the setting.
Our speaker is familiar with both the Old Testament of the Bible and old John Wayne movies and spaghetti westerns. He seems to want his listener to think of the Vietnam War without having to say the words "Vietnam War."