No video of this ever but now here's a crappy but listenable sound recording. For a flavor of the angry responses to electric Dylan from a large part of the crowd check out the Intro and the Intermission comments (with Murray the K), and then at end of songs in second half when there's a lot of booing and so forth. The band includes Robbie Robertson on guitar and Levon Helm on drums. (Note: I see Dylan live in Buffalo a few months later and protestors brought cowbells.) Watch Harvey Brooks, the bass player, talk about it here. Here's a Wikipedia account:
Photographer Daniel Kramer, who accompanied Dylan to the Forest Hills concert, wrote: "Dylan held a conference with the musicians who were going to accompany him in the second half of the concert. He told them that they should expect anything to happen—he probably was remembering what occurred at Newport. He told them that the audience might yell and boo, and that they should not be bothered by it. Their job was to make the best music they were capable of, and let whatever happened happen."
Musician Tony Glover, in his liner notes for the Bob Dylan Live 1966 album, quotes a contemporary account of the concert from Variety: "Bob Dylan split 15,000 of his fans down the middle at Forest hills Tennis Stadium Sunday night... The most influential writer-performer on the pop music scene during the past decade, Dylan has apparently evolved too fast for some of his young followers, who are ready for radical changes in practically everything else... repeating the same scene that occurred during his performance at the Newport Folk Festival, Dylan delivered a round of folk-rock songs but had to pound his material against a hostile wall of anti-claquers, some of whom berated him for betraying the cause of folk music."