Dylan often draws on the mythology of the American West, like gamblers, prostitutes, and outlaws. In this song, he draws on the loneliness and cultural isolation of the West, and the watchtowers are literally the last "frontier" of civilization.
- Verse 1: Calling the two characters the "joker" and the "thief" is a form of metonymy, where some attribute of a person or thing is taken as representative of the whole. In this case, joking and stealing are actions that represent the essence of these two men. It's not all they do, but for the purpose of the song it's all that matters. Also, it's just our interpretation, but the joker and thief seem to belong to the general class of outlaws, which fits in with some of the other symbols of the American Old West in the song. In the mythology of the West, just like in this song, people who live at the margins of society are often the most virtuous. (Another example is the prostitute with a heart of gold.) Thus, we like the thief and even think he's kind of wise – even though he's a thief.
- Verse 8: Again, this might be a bit of a stretch, but the image of dusk or sunset implied by the expression "the hour is getting late" seems to belong to the mythology of the American West and cowboy culture. Think of the moment in Western films when the sun is setting and the hero is about to be caught in a dangerous place after dark. A moment like this occurs in the first Star Wars (well, Episode IV), when Luke Skywalker has to hang out in Old Ben Kenobi's cave to avoid the Sand People who come out after dark. (And if you don't think Star Wars is inspired by old Westerns, think again.)
- Verses 11 and 12: The last two verses of the song present more imagery of the West. The growling wildcat, the slightly scary approach of two anonymous riders, and the howling of the wind add to the suspense and make us think that something is about to happen. Wildcats were a fearsome aspect of frontier life, and this legacy remains with us today: think of how many American sports teams are named after them.