Hi Greg
I was taking guitar lessons back in 78' from a friend, I didn't know a thing about guitar's or about playing them, today I only know a tiny bit more but the friend Rob Joel was showing me (trying to show me) a bass run going from C to G & back again. Where my thumb hit the A sting on the 3rd fret I was to then take my index finger off the A put my next finger that had been 2nd fret of the D string & put it on the 2nd fret of the A sting then pick with the thumb then play the A string open then go into the G cord, picking E again with the thumb first as I started to play the cord. I was having trouble going back & forth with this when he said "it's simple & it's lovely, I taught Joan Baez that" I stopped & asked him "what". Turns out he was pretty fond of the kid who he said had the dirtest feet in Cambridge & it turns out that he said he had taught or showed her a number of things on the guitar. You mentioned above that her playing reminded you of Mexican and Spanish-style guitar. Well I never heard Rob play much of that style, maybe a couple or 3 times but during my lessons he got to showing me some Spainsh flamingo style (& other styles) trying to explain different technique & different styles that went way over my head, maybe she got it from him. He was a great singer & always amazed me with the his wealth of knowledge about the songs he did (never the show off, mind you). I'm not sure why but he was a mentor to me, I think he was fond of my street background. I wouldn't be surprized if he seen Joan in the same way. He certinally was right there at the time, would've given a youngster a helping had at the drop of a dime & I'm sure he was looked up to & sought out by quite a few, it being his nature to be so approchable & accomadating. He did have a father like grin when he talked about her. I guess I should find out more about Rob from those times. I moved to Hawaii not long after starting lessons with him. Forgot how he taught me, got to practicing things all backwards & just got worst & worst until I deceided I should keep my friends & stop. While I was living out there in Hawaii Rob passed away, it was quite a while before I found out, I really was very fond of him. He always said the the VA would always be checking him out (medicaly) to find out why he was still alive after the war (WWII, I think)
If you watch the u-tube linked above about 1:09 minutes into the song you'll see Joan doing the run as I discribed above, going from C to G & agin shorly after that. (I didn't watch all that much)

Barry