Cyberspace is defined with the word "hallucination", and Gibson spent 1977-1983 writing his short fiction and first novel on the subject. The degree to which he was influenced by psychedelic culture is open to debate, but I agree that it was non-zero. I think Grateful Dead tapes is your own projection, however. Bob Marley is more likely as muse-ic.

Yup, there’s righteous dub involved in orbital adventures