- Please keep these annotations SPOILER-FREE by not revealing information from later pages in the novel.
Page numbers refer to editions with 369 pages, where the story begins on page 1. Not sure if there are other editions with variant pagination. Please let us know otherwise.
A hill in Ojai where an institute run by the Theosophical Society in America is currently located.
The name may refer to three-ply plywood. Basic run-of-the-mill (literally) plywood that's used in quantity for sheathing when building houses is often three-ply. This is, perhaps, consistent with the paragraph describing him, which mentions two other building products (aluminum siding and screen doors) and alludes to some event that has "torqued him out of tolerance," as might happen to plywood that has been misused and become twisted.
Jiddu Krishnamurti was a prominent Indian-born spiritualist who did, in fact, live in Ojai.
Shaggy . . . Scoob
Characters in the cartoon Scooby Doo. An appropriate reference since the cartoon first was aired in 1969 and involved solving mysteries.
edges of cliffs in Hawaii
This passage about suicidal love sick men is strikingly similar to one in Vineland:
- Hawaii is where men from California bring their broken hearts, seeking exotic forms of self-injury not so readily available on the mainland. Some specialize in active volcanoes, others in cliff diving, many go for the classier swimming-out-to-sea option. I can put you onto several travel agents who offer Suicide Fantasy packages, if you're interested. (p. 60)
"...put everything in the Ostracizer and made smoothies..."
Denis means Osterizer, a brand of blender or food processor.
Didn't you see that movie?
Denis is referring here to the 1932 film Freaks, a horror film about sideshow performers with a cast of actual sideshow performers.
The Shasta/Mickey story shows some similarities to the central love story in the film. A "normal" and beautiful woman pretends to love--and marries--one of the "freaks" simply for his money. The freaks revolt against her and maim her, ultimately turning her into freak show exhibit.
Code of the Freaks
is the "code of ethics" that the sideshow performers in Tod Browning's movie "Freaks" build up among themselves, "to protect them from the barbs of normal people. Their rules are rigidly adhered to and the hurt of one is the hurt of all; the joy of one is the joy of all." 
Completely irrelevant trivia: Tarzana is named after Tarzan because Edgar Rice Burroughs (the author who created Tarzan) was a prominent citizen. More here.
Gleichschaltung Model 33 Automatic Bazooka
Gleichschaltung, meaning "coordination," "making the same," "bringing into line," is a system the Hitler regime developed for the complete forcing into line of German society in terms of politics, information and culture. Gleichschaltung's system established totalitarian control over the individual, therby forcing the individual/society to follow a specific way of thinking using an oppressive police force. It started, unsurprisingly, in '33. 'Schaltung' in German also refers to gears and switches (often, but not exclusively those of cars), so it might also refer to the bazooka's automated mechanism here.
dead people who do and don't come back
Sounds like the Thanatoids in Vineland.