I don't really know this album at all (not a Dylan fan) but I found an interesting interview in the
March/April 1974 issue of
Recording Engineer/Producer with engineer Rob Fraboni, who engineered the album, and Dick La Palm, manager of the Village Recorder studio where the album was done.
There isn't much about quad in the interview, but Fraboni does mentions that he's working on the quad mix for the album at the time that the interview was conducted:
This is somewhat "new" information as the jacket for the quad LP just reused the stereo artwork so there was no confirmation that Fraboni did the quad mix as well, until now.
If you like Dylan, or have an interest in recording and mixing, I think the interview (which starts on page 19) is well worth a read - it does get overly technical at times (I think there's a whole page on what kind of microphones were used, and how) but there's a lot of interesting information about how (and when) the album was recorded, and the amount of input that both Dylan and Robbie Robertson had on the sound and final mix. I've always felt that in one way, albums are kind of like an aural document of work that was undertaken, so to have more information about that work just adds more context that only serves to deepen my appreciation of what I'm listening to.
As a side note, it's interesting just how much stuff it seems was mixed for quad at the Village Recorder, a relatively "less famous" studio compared to the Record Plant, Capitol Records, or the Warner or CBS studios. Not only was this album mixed there, but Ed Michel and Baker Bigsby did most (or all?) of his ABC/Imuplse!/Bluesway quad mixes at the Village Recorder, and apparently
some of the Fantasy/Prestige/Milestone quad work was done there too.