I think that's an accurate description, my personal inclinations are to strip away the woo-woo language that Watts always uses, though.

Up to the "voiding the void" part, yeah, that's as accurate as you're going to get without trying it for yourself. There's definitely some burners I know that trip waaaay too often (and it shows), maybe that's what he means by saying "letting go of the void"? Like, not trying to regenerate some sublime experience that is dependent on particular circumstances or something?

I dunno, I think if someone is searching around in stuff like DMT, especially since they are so much more well-known nowadays, they're looking for something in general, and hallucinogens offer a vague enough notion that something major has happened in you, not to you.

There's also Doors of Perception by Aldous Huxley, he experimented with mescaline loooong before it was the pop culture thing it is now and he didn't have much background besides folklore to go on. I read like 10 years ago though, so it may not be as good or thoughful as I remember. 16 year old me says go for it, though!