Original text: We could just as well of rode clear to the ranch if that bastard bus driver knew what he was talking' about. This is uneducated speech of the 1930s in the U.S. We could [just as well] of rode ... => [Just as well] we could of rode ... => We could of rode ... => We could've rode [Note - Native speakers often write "could of" for "could've" because "of" and "'ve" are both pronounced as "uv." More information: https://www.italki.com/article/276/what-does-would-of-mean-dont-make-this-english-grammar-mistake] => We could've rode => We could've ridden [note - Poorly educated speakers tend to use the simple past form for the past participle. Examples: I go, I went, I have went. I could have went. I could've went. I could of went.] if that bastard bus driver knew what he was talkin' about. => if that bastard bus driver had known what he was talking about. full meaning: We could have ridden the bus all the way to the ranch if that bastard bus driver had known what he was talking about [= had known that the ranch was on the bus route].

I differ a little with Chris, in that I find 'We could just as well..." is more idiomatic speech than an uneducated style. I hear people of certain backgrounds speak this way from time to time in Australia and they are not uneducated - it's just a language style they have inherited. 'We could just as well as well of rode clear to the ranch' means "We may as well have ridden straight to the ranch'" or "It would have been just as good a choice if we had ridden straight to the ranch". They are *almost* saying, "We should've ridden straight to the ranch".