I was a little disappointed that a "transwarp" type drive would be based in a galactic bionetwork rather than more fundamental physics principals, though Stamets does note in E03 "At the quantum level, there is no difference between biology and physics. No difference at all."
And then in E06 he says re "SarekVision"
"I gotta say, this katra stuff is way cool.
An uncharted superhighway connecting all of consciousness and life?" I would relate that to quantum entanglement, where the idea of so-called non-locality implies connectedness across vast distances, even light-years with no time factor at all. This melding of spacetime and thought/consciousness is also related to the mind-based transport capabilities of TNG's Traveler - skill's even human Wesley was able to start to work with.
My point being, that STD is quickly bringing up the complex and fundamental relationships between spacetime, thought, energy, and the concept of universal connectedness outside of time through a fundamental underlying medium, that of the very nature of existence.
Empty space, a pure vacuum, is not a nothingness at all, but is rather an everythingness, and has infinite so-called vacuum energy, with a "quantum foam" in which virtual matter / anti-matter pairs are constantly emerging, and recombining back into the vacuum. Indeed, when one of these pairs emerges from the vacuum at the event horizon if a black hole, one of the pair can get pulled into the black hole, while the other can escape, and this is the basis of "Hawking Radiation".
So Spore Drive is an experimental technology, and as STD develops, they are getting an ever-deeper understanding of these profound phenomena and their interrelationships, so "Spore Drive" may just be a starting point to more profound technologies for getting around the galaxy, and beyond. Using spores initially may in part be a plot device to help part of the audience unfamiliar with deeper more abstract physics, have something more physical to hold on to while coming to terms with the more abstract aspects.
And lastly, I would note that these ideas of a deep fundamental and time-free interconnectivity of all places, things, entities, and life, is not only an emerging concept in real-life and trek physics, but is something that has been appreciated and taught by mystics for thousands of years in Vedic and Eastern Wisdom Traditions. These ancient mystics or mind-consciousness-explorers, did not have modern tech or particle accelerators to explore the universe, but they did have their minds, and the ability to explore the universe from within at the deepest levels.
Albert Einstein first came to terms with his revolutionary concepts about the nature of light through thought experiments. And so like the mystics of old, he found the deep principles of the universe available from within his mind, because individual mind, and "cosmic mind", are inextricably linked, and some would say synonymous.