katpepul,
Welcome to the forum. Being a long-haired "freak" from the sixties, I was a huge fan of Iron Butterfly. Like many other groups of the time, they were much more than just musical groups. They were "voices" of the generation that was completely misunderstood and corruped in the years that followed. They were "psychedelic" in that they experienced first-hand what it meant to have their consciousness "expanded". I believe that this period in time was a "great earthquake" that has been prophesied. This period changed the whole world and made the search for "life, the universe and everything" an everyday byword. I also believe that the very reason that this bassist you speak of was interested in light travel to begin with was because he "experienced it" firsthand. Most of those I know of from the period also had similar experiences of "exiting" this universe and entering another that was just as viable--if nor more so--than this one. Time and dimensional "travel" was quite common during this period. I heard many people speak of it and, without exception, their "comeliness turned into corruption". This entire period was markedly one of self-retrospection and then self-expression which changed everything--right down to the nuclear family unit. Everything that was then held as sacred, was seen to be illusion and a search for truth began that was, to me, a renaissance of sorts. The very deep-rooted things that people are searching for today had its roots in that movement that has gone underground but has not disappeared.
Of course, the "drugs" of the period had a lot to do with the consciousness explosion, but it also had a great deal to do with the mind-set of many people of the period. Many of the people who "took" these drugs simply "whacked out" and ended up psychological basket cases. No one of sound mind ever suggested (except people like Timothy Leary) that the general populace start taking these strong drugs. They were(and are) extremely dangerous. However, to some (perhaps like the bassist you speak of), this was a doorway into a place that was "home" to many. "There", you could "see" music, and taste it as well. You could literally experience the geometry of space-time and manipulate it at will. All the senses carried varied experiences and some felt literally "blind" when "coming down". When many of these groups of the period sang, they were singing from these "places". Those who "heard" them, "went" there with them. It was no mystery, but there was also a great longing to be able to communicate this "experience" to others. That was where the mystery lay. How to bridge this gap between the "knowing" and the unknowing? No source of information was anathema. Anything that could be used to communicate this knowledge was utilized on every scale. Only now, is science reaching this point in their understanding and becoming willing to put everything on the table--including the esoteric. Nothing is taboo anymore, but this was common then. It is almost like we are "growing up" as a species. We are exactly where we should be in our maturation process.
I, too, would be interested in what others come up with on this. It sounds like you are talking about one of the "brothers". Thanks for bringing it up.