I’m not sure how to experiment with or falsify this idea as it has truly abstract components (clever thought experiments?). If well-founded (is it?), do you think an idea should be abandoned if it cannot be verified? A satisfying material description of consciousness still eludes us so, if an abstract consciousness does exist outside of physics . . . it's not outside of Nature!

"Specifically, is the MTN network in animals with the very simplest nervous systems observable, and is the functioning of that network necessary to explain the behaviors of those animals? I'm skeptical of that."

I think it must be observable by now(?) and, according to this idea, it’s activity is necessary to explain behavior. TMI, but we need to see how the conformational patterns of microtubule proteins correspond to the human report of experience. That, at least, would seem very falsifiable and will suggest whether the larger idea is compelling or not. Do you know of a lab-full of graduate students or senior neuroscientist who may be interested in this?

"And what about the behaviors of plants, which lack nervous systems at all. Are you proposing that they have some equivalent of MTNs that relate their abstract minds to their physical embodiments? Where are those MTN-equivalent networks located in a simple multi-cellular plant, or even in a single-celled bacterium? "

I think all cells have a cytoskeleton formed of microtubules (MT’s) but I’m not sure if cells outside of the brain or nervous system—cells without axons or dendrites—can form a microtubule network (MTN). That is, without an MTN, the vibrational idea (Vi) of a plantcertainly has an awareness, though, it's nothing like your experience.