I did some dabbling in astral travel when I was in my late teens, and diligently studied Abramelin methods as well as those of Crowley et al. My adventures in such were brought to an abrupt halt when I can only say that I experienced either a one time, transient psychotic break or encountered things which I was vigorously convinced needed no more of my tender attention.
These experiences, tempered by time and augmented by some other observed and documented phenomenon in my life, led me to reanalyze the Abramelin translations in an effort to elucidate the key elements and remove the hocus-pocus aspects.
The hypotheses that I currently hold is that if there is anything to any of this besides distorted perception, it is implicit in a many-worlds observation, in that the bandwidth of probabilities within which we can observe may be somewhat malleable through the appropriate application of isolation from entangling casual interactions and intentional observation. We see some support for this hypothesis through probability manipulation vis-a-vis casimir fields and restrictive cavities.
Adjacent to this is a hypothesis that the web of electromagnetic fields carrying data in which most of us are intertwined, along with other forms of instantaneous communication makes casual isolation exceptionally difficult in the 21st century, as causal relationships leak in even in the subtle vibrations of water molecules or anything else that might respond, down to a quantum scale, to information carrying RF signals. This could, in concept, limit efforts to broaden the spectra of observable universes in a similar way that casimir cavities limit the casimir force experienced within. By introducing causal entanglements, we narrow the possible observations.
Anyway, my intrinsic belief is that the universe is dark, and cold, and full of terrors lol. Explore carefully, kids.